I love how you describe your thought process along the way to find the problem(s). It's a real pleasure to be able to watch a master show how it is done, and done right.
It never ceases to amaze me how often it's the power supply. I got a non-working HP 3561A that was in beautiful physical condition a few years back for a song from the Bay of Evil. The issue with it turned out to be a single shorted diode in the 8V power supply. I 'temporarily' put in a 1N4148 for troubleshooting purposes; six years later it's still there. Edit to add - you've got to love the attention to detail and clever design of this era's gear from HP - so easy to service with the arrangement that lets you lay it on its side and, by removing a few nuts, swing the boards out like the covers of a book to troubleshoot without disconnecting anything.
Thanks for explaining that the B model doesn't have the clunking relays. I was beginning to wonder if I had issues with mine until you stated that. Great job!
Buddy, good job, step by step. So what appears as a mountain that can´t be climbed turns out to a big win. So we learn: First things firts, keep calm and do not loose focus- Great video! 73 de Olaf
The biggest problems repairing HP RF gear of that vintage are that often the transistors and integrated circuits used in the design have been selected for performance, and are "HP house-marked". In addition, if you want to keep it looking "original", getting new components in the same sized older formats can be very difficult and/or expensive! That said, the build quality of those old units is usually to the highest standard.
@@hectorpascal Well said Hector. And I agree, custom parts are hard to come by. Some Tektronix scopes are impossible to repair unless you are will to jump through hoops and change the design a bit.
I'm very pleased to see this video because I own one of these generators that I bought on Ebay and have not tested it yet be cause I was still constructing an isolated variable current limiting line supply. Now I'll know what to expect when I test run the unit. Thank you so much for the vids.
Great Video Buddy. I'm working on an HP1710B with a lot of issues, some due to failed components some due to previous failed repairs. I think I'm the 5th person to look at this 'scope. The hardest problem is understanding the very interdependent LVPSU, where the +15 is used as a reference for most of the other voltages, but the +15 is dependant on the +53.3V rail, which uses the +15 as a reference. I have broken down the individual rails as much as possible, and found that some of the transistors were 'replaced' in the wrong spots, even a few missing zener diodes as well. It sure is a challenge being the guy at the bottom of the cliff. Anyway the customer had a 100Mhz HP scope, which he offered as 'spares', but my test showed it works 100%, so in the end he took that back, and gifted me the 1710B. And that is the only reason I'm still working on it, when I have a spare minute or two. Hope you had a good Easter. Andrew
Wow Andrew, sounds like a bit of work ahead of you on that unit. I do not recall ever working on one of those but have seen that reference scheme before. Has a great Easter here and hope you did also. Thanks for watching.
What a great way to start my day and see this video posted! :) Buddy, I cant thank you enough for working on it but also show how you troubleshoot it along with the cause and effect, this was definitely above my scope! Looking forward to playing...er I mean using it. Will be waiting for your email. ~Jack, VEG
Good job Buddy...wish I was having as much good luck troubleshooting my Rohde & Schwarz spectrum analyzer that gave up the ghost! It's really hard when you don't have schematics available.
Great video, thanks for sharing. You may have noticed by now that those small cylindrical fuse packages actually unplug from the board, they're plugged into tiny sockets.. Takes a little gentle wiggling, but they do unplug. I bought a 8656A pretty cheap on ebay, and there was no signal output. It turned out to be that the 1amp fuse for the +15v rail was blown (F3). I had some of those fuses in stock. Replaced it and monitored it for awhile and the circuit never drew more than 354 milliamps when I monitored it for awhile. So far so good.
Top analysis Buddy I’ve got the 8657B and i need to find time to check it as output has stopped but front is working just no output. I’ve still got the BK 2040 that Mike calibrated for me and a spare also. But occasionally i need the HP for radios outside the CB band. Yes the online manuals you find are often not of a high quality. When i scan manuals if the page is important for details it doesn’t get compressed as do a lot of the text pages but i still scan at 600. Take care Buddy will email you soon.
Great job, Buddy. It's just like you to tackle a tough, multi-layer problem and breeze through it as if it was easy. Thanks for sharing it with us. 73 de K7RMJ Frank
Hello Buddy! good to see you again! Great video as always! I have the HP 8656B variant like the one that you use on your bench. I use it a whole lot, and have had no problems with it so far! I think it would be a good idea for me to open it up and give it a good general inspection and to see what the ratings of the electrolytic caps are so that I can order a replacement set so when I get the time I can replace the old ones to prevent a future problem! Thanks for the video! and best wishes! John Bellas KC2UVN and 73's
Thanks John, always a good idea to replace the main filter caps. The silver ones should be good. Also check the insulators under the regulators for cracks and dry up. Thanks for watching.
Thanks for the wonderful presentation. I am working on a HP 8656B, my problem was much easier, the .086" hardline from attenuator output to front panel N connector was damaged, making no connection. Will be fixed tomorrow when replacement arrives and is installed. Chuck W9KR
Nice explanation of your troubleshooting of this fine generator. I was just curious as to why you didn't start with disconnecting J2 and measuring the 3 voltages in the DIP socket first. That would show the status of the power supply without any load. Why start with checking individual components first?
Thanks and good question. I could have put this on the bench and had it running with in 15 minutes. Not because I think I am all that lol, but Jack has already done 3 videos on this very unit. So really I had what I needed to go directly to the problems and try and make the video as interesting as I can,. Now if this was just some unit I knew nothing of, may have done it the same way. They are parts here that cannot be replaced in vintage gear. We were able to find the failures with out even powering up the rig. The minus 15 volt regulator was drawing a good amount of current so it could had shorted at any time. Thanks for your question and thank you for watching.
Nice of you to notice those details Bill. Pin 2 was 5 volt output, pin 3 was minus 15 volt output. Capacitor lead was just inserted to make some test and then supply missing voltage. I have swapped it between the two several times, May could have been camera angle but probably just where I was testing and left it. Thanks
I like those HP's I keep an eye out for 1 to be sold on ebay ETC. I have a Tenma 72 380 , but it doesn't have the option to select the modulation percentage...... Someone mentioned to me that they think it has the 30 percent modulation is automatically there ....
Buddy… Great video! Two questions: Did you end up replacing the three 3200uF and the one 24000uF filter capacitors? I currently have an 8656B on my bench with similar issues and cannot locate these caps. Looked on Mouser, Digikey, and Newark and no one has them. I am racking my brain seeing if perhaps I can cobble up a parallel capacitor arrangement, but the individual smaller caps are hard to find too. I know you’ve been very busy, but would love to hear your thoughts on this. Thanks as always.
The 8656A was the worst signal generator ever made by HP. My company bought one new in the 80s and used it for testing marine radios. It had very poor close in phase noise, as a result of the synthesizer fine loop using a 100Hz reference frequency at the phase detector. The very large multiplication factor in the loop resulted in very poor phase noise at offsets < 100Hz. They discontinued the A version very quickly, and replaced it with the B version, which used a fractional N synthesizer for the inner loop. So avoid the A version!
Great diagnosis, Buddy!! I am thinking i have never seen a -15 volt regulator in a TO-3 case. The TO-3's are rated 5 amps if i remember correctly. i saw the Sencore SC61 on the bench. I just picked up one on EBAY as you recommended it. However, i did not get any probes with it. can you enlighten me as to what the value of the X 10 probe resistor should be? also what the capacitance of the low cap probe should be. P.S. i finally got the varactor diodes for my Sencore CB42. I'll let you know how that turns out.
Sounds good on the CB-42. I will look that information up on the scope. But if you have downloaded the manual it is also in there for the probes. Has all the specs. The original probes are a bit pricey but well worth it.
You got an easy one Buddy :) I have a pair of HP 3314A generators on the bench and man... lot's of issues. Usually HP equipment is well designed for repair but these units have everything shoe-horned into a small (1/3 rack?) form factor with some _weird_ inter-board connection solutions. My other HP 8647A was a lot easier to service. Regarding the small silver/aluminum Sprague axial caps, personally I'm _on the fence_ as to replacing them in my machines right now. I am pretty sure they are hermetically sealed and so should still be good. Will not know for sure until my ESR tester gets here. Are you planning on re-capping those as well? Curious to know what you and others think about that. The same style caps in my two generators currently "under the knife" are now pushing 40 years old... Cheers,
You have your work cut out for you with them! Good luck Eddy. I will try and give my honest opinion on capacitors. Those silver caps where probably better than anything you can get today. If the ESR is ok, leave them. But with the larger color electrolytic, they have to go. Sort of like the Yaesu FT-101, after all the units I have worked on, I never replace a electrolytic in one because it was bad. Most of the time the owner wanted them replaced. Cannot say that for Kenwood and Icom of that same vintage. HP spared no expense. Thanks for watching.
@@TheRadioShop - Thanks for the info. Yep, I was wary of doing a complete re-cap on them and put that task off. Will test the Sprague caps and if still good (probably) will leave them alone! I have already re-capped the bigger PSU ones, the new replacements are smaller so more free space on the PCB now (and lighter). I have the issue on one unit mainly sorted (E30/CAL on all ranges) I traced it to a problem in the SYNC circuit which eventually goes into a CPU based frequency counter. Maybe I should do a video vignette on what I find... something to think about. Cheers and take care now.
New fan and subscriber! Wonderful channel, and I’m looking forward to watching EVERY SINGLE ONE of your videos, and learning as much as possible. May I ask: Have you done a video, or if not, COULD you make a video, or just reply here, talking about how you got to where you are now; how you learned what you know. This FASCINATES me (how people gain their skills), because it reminds me that what one man can do, another can learn. MOST people tell me they’re self taught, and that they just started tinkering, and just did it for years, and now here they are. SOME have been formally trained though, or have military or industrial experience. Even if you’re self-taught though, I’d LOVE to hear about your beginnings and how you got to where you are. Thanks so much! 😊😊😊
Thanks Steve and welcome to the channel. I have not done a video on how I got started, but have mentioned it in several videos. I will put that in the que to do some day soon. And yes, I am self taught, started at the age of 12. Have worked for Curtis Mathis, General Electric, and EF Johnson. Hope you enjoy all those videos and thanks for watching.
Bonjour, je viens d'acheter un r&s smg rf generator, j'espere que je n'aurais pas de surprise avec. Je vais de ce pas le brancher. C'est 15 kg plus lourd que l'entrée de gamme siglent et moitié moins cher, j'ai hésité, maintenant que je l'ai, je vais le brancher et on verra bien. 🤔
I love how you describe your thought process along the way to find the problem(s). It's a real pleasure to be able to watch a master show how it is done, and done right.
Thanks for your very kind comment
Hey , Buddy if you are interested ., I need a radio repaired but no time frame If you are good on the Qrz I sent you mail. thanks!
What high power said!!!!!
It never ceases to amaze me how often it's the power supply. I got a non-working HP 3561A that was in beautiful physical condition a few years back for a song from the Bay of Evil. The issue with it turned out to be a single shorted diode in the 8V power supply. I 'temporarily' put in a 1N4148 for troubleshooting purposes; six years later it's still there.
Edit to add - you've got to love the attention to detail and clever design of this era's gear from HP - so easy to service with the arrangement that lets you lay it on its side and, by removing a few nuts, swing the boards out like the covers of a book to troubleshoot without disconnecting anything.
I love this older electronic equipment, even with my poor eyesight and fat fingers I can still work on it. Modern SMD stuff leaves me cold.
Thanks for letting us look over your shoulder.
Thanks for explaining that the B model doesn't have the clunking relays. I was beginning to wonder if I had issues with mine until you stated that. Great job!
Thanks
i had an 8656B wish i still had it. nice troubleshooting
Great and fascinating to see you work on this beautiful piece of equipment. Thanks for sharing, Buddy, always a treat!
And thank you for watching. Will work like a bought one soon.
Buddy, good job, step by step. So what appears as a mountain that can´t be climbed turns out to a big win. So we learn: First things firts, keep calm and do not loose focus- Great video! 73 de Olaf
Much appreciated my friend
Old HP equipment was beautifully designed and built. I have not seen the inside of any current HP equipment.
Thanks for the lesson Buddy.
The biggest problems repairing HP RF gear of that vintage are that often the transistors and integrated circuits used in the design have been selected for performance, and are "HP house-marked". In addition, if you want to keep it looking "original", getting new components in the same sized older formats can be very difficult and/or expensive! That said, the build quality of those old units is usually to the highest standard.
Thanks and I agree on the design.
@@hectorpascal Well said Hector. And I agree, custom parts are hard to come by. Some Tektronix scopes are impossible to repair unless you are will to jump through hoops and change the design a bit.
Buddy - great job troubleshooting the power supply section. I know Jack will be thrilled to get this back in his shop in working order. Best, Don
Thanks Don and appreciate you stopping by
I'm very pleased to see this video because I own one of these generators that I bought on Ebay and have not tested it yet be cause I was still constructing an isolated variable current limiting line supply. Now I'll know what to expect when I test run the unit. Thank you so much for the vids.
Great video enjoyed watching you go through the troubleshooting process
Thanks for watching
Great troubleshooting on this HP unit Buddy. It was definitely in good hands!
Thanks 👍
Your on the right path... you found it!!!
Great fix Buddy!
Thanks for stopping in Bill
Great Video Buddy. I'm working on an HP1710B with a lot of issues, some due to failed components some due to previous failed repairs. I think I'm the 5th person to look at this 'scope.
The hardest problem is understanding the very interdependent LVPSU, where the +15 is used as a reference for most of the other voltages, but the +15 is dependant on the +53.3V rail, which uses the +15 as a reference. I have broken down the individual rails as much as possible, and found that some of the transistors were 'replaced' in the wrong spots, even a few missing zener diodes as well.
It sure is a challenge being the guy at the bottom of the cliff. Anyway the customer had a 100Mhz HP scope, which he offered as 'spares', but my test showed it works 100%, so in the end he took that back, and gifted me the 1710B. And that is the only reason I'm still working on it, when I have a spare minute or two.
Hope you had a good Easter.
Andrew
Wow Andrew, sounds like a bit of work ahead of you on that unit. I do not recall ever working on one of those but have seen that reference scheme before. Has a great Easter here and hope you did also. Thanks for watching.
Excellent job Buddy this was very informative. It is always a good day when you have a new video posted.
Thanks you my friend.
Great video of a very logical process to find the problems on this unit. Thanks for sharing.
Thanks for watching Bill.
What a great way to start my day and see this video posted! :) Buddy, I cant thank you enough for working on it but also show how you troubleshoot it along with the cause and effect, this was definitely above my scope! Looking forward to playing...er I mean using it. Will be waiting for your email. ~Jack, VEG
Thanks Jack, was going to mail you when I got home but you saw the video before I could, will be mailing you soon my friend.
Good job Buddy...wish I was having as much good luck troubleshooting my Rohde & Schwarz spectrum analyzer that gave up the ghost! It's really hard when you don't have schematics available.
Hi Dino. I agree, with out schematics it make a job really tough. If I can help in any way let me know.
Great video, thanks for sharing.
You may have noticed by now that those small cylindrical fuse packages actually unplug from the board, they're plugged into tiny sockets.. Takes a little gentle wiggling, but they do unplug.
I bought a 8656A pretty cheap on ebay, and there was no signal output. It turned out to be that the 1amp fuse for the +15v rail was blown (F3). I had some of those fuses in stock. Replaced it and monitored it for awhile and the circuit never drew more than 354 milliamps when I monitored it for awhile. So far so good.
Top analysis Buddy I’ve got the 8657B and i need to find time to check it as output has stopped but front is working just no output.
I’ve still got the BK 2040 that Mike calibrated for me and a spare also. But occasionally i need the HP for radios outside the CB band.
Yes the online manuals you find are often not of a high quality.
When i scan manuals if the page is important for details it doesn’t get compressed as do a lot of the text pages but i still scan at 600.
Take care Buddy will email you soon.
Hi Peter. That should be a fairly easy fix. Check the voltages first.
Nice catch,
Good seeing you
Always a pleasure to see you drop by Sue. Hope you are doing good.
Another great job your the best. 73 Buddy
Thanks you sir
I REALLY LIKE your Videos!
No dought you're the Electronic repair Man!
Glad you like them!
Love that signal generator 😊
Good procedure to figure it out . Curious about the tone generated and if it works .
Great job, Buddy. It's just like you to tackle a tough, multi-layer problem and breeze through it as if it was easy. Thanks for sharing it with us. 73 de K7RMJ Frank
Thanks Frank. These are not to tough to work on. But like you said multi problems can really miss lead you.
Hello Buddy! good to see you again! Great video as always! I have the HP 8656B variant like the one that you use on your bench. I use it a whole lot, and have had no problems with it so far! I think it would be a good idea for me to open it up and give it a good general inspection and to see what the ratings of the electrolytic caps are so that I can order a replacement set so when I get the time I can replace the old ones to prevent a future problem! Thanks for the video! and best wishes! John Bellas KC2UVN and 73's
Thanks John, always a good idea to replace the main filter caps. The silver ones should be good. Also check the insulators under the regulators for cracks and dry up. Thanks for watching.
Merci pour cette vidéo qui va me permettre de dépanner mon Générateur HF
Great video Buddy!
Thanks Michael
with all the crowbar's shorted, I wonder if someone connected to to 240v while set to 120v or was it a big surge/storm damage.
It does make you wonder. But something surly happened.
Another good job I enjoy watching you I wish I had half of your knowledge I’d be in good shape God bless
Thanks 👍
Love the intro jingle, Buddy!
Great work. Thank you
How did you solve the 3A in 5V rail?
Thanks for the wonderful presentation. I am working on a HP 8656B, my problem was much easier, the .086" hardline from attenuator output to front panel N connector was damaged, making no connection. Will be fixed tomorrow when replacement arrives and is installed.
Chuck W9KR
Seen that before Chuck. Thanks for stopping by.
the ups driver droped mine on the front porch . sounded like a tree falling they don't have a complaint dept
Nice explanation of your troubleshooting of this fine generator.
I was just curious as to why you didn't start with disconnecting J2 and measuring the 3 voltages in the DIP socket first.
That would show the status of the power supply without any load.
Why start with checking individual components first?
Thanks and good question. I could have put this on the bench and had it running with in 15 minutes. Not because I think I am all that lol, but Jack has already done 3 videos on this very unit. So really I had what I needed to go directly to the problems and try and make the video as interesting as I can,. Now if this was just some unit I knew nothing of, may have done it the same way. They are parts here that cannot be replaced in vintage gear. We were able to find the failures with out even powering up the rig. The minus 15 volt regulator was drawing a good amount of current so it could had shorted at any time. Thanks for your question and thank you for watching.
Another great video!!!
Mouser has those fuses.
Thanks, also found them on Newark
Nice work Buddy. It looked like you had the capacitor leg in pin 2 of the socket instead of pin 3. Maybe just the camera angle. Thanks
Nice of you to notice those details Bill. Pin 2 was 5 volt output, pin 3 was minus 15 volt output. Capacitor lead was just inserted to make some test and then supply missing voltage. I have swapped it between the two several times, May could have been camera angle but probably just where I was testing and left it. Thanks
I have the 8657B Version , I love it never any problems but the Fans on these are so Noisy
I like those HP's I keep an eye out for 1 to be sold on ebay ETC. I have a Tenma 72 380 , but it doesn't have the option to select the modulation percentage...... Someone mentioned to me that they think it has the 30 percent modulation is automatically there ....
Do you have part numbers for the replacement components? I have an A model and is working well so far. Great video!
Buddy… Great video! Two questions: Did you end up replacing the three 3200uF and the one 24000uF filter capacitors? I currently have an 8656B on my bench with similar issues and cannot locate these caps. Looked on Mouser, Digikey, and Newark and no one has them. I am racking my brain seeing if perhaps I can cobble up a parallel capacitor arrangement, but the individual smaller caps are hard to find too. I know you’ve been very busy, but would love to hear your thoughts on this. Thanks as always.
do you work on older cb radios? like an old GE superbase? belongs to an old friend of mine. it has low output.
I have not worked on cb radios for many years now. Sorry
The 8656A was the worst signal generator ever made by HP. My company bought one new in the 80s and used it for testing marine radios. It had very poor close in phase noise, as a result of the synthesizer fine loop using a 100Hz reference frequency at the phase detector. The very large multiplication factor in the loop resulted in very poor phase noise at offsets < 100Hz. They discontinued the A version very quickly, and replaced it with the B version, which used a fractional N synthesizer for the inner loop. So avoid the A version!
12:11... pins 1 and 2 are anodes
Bruce, you are correct
I have a full Collins station. I could use your help. Can you assist?
Great diagnosis, Buddy!! I am thinking i have never seen a -15 volt regulator in a TO-3 case. The TO-3's are rated 5 amps if i remember correctly. i saw the Sencore SC61 on the bench. I just picked up one on EBAY as you recommended it. However, i did not get any probes with it. can you enlighten me as to what the value of the X 10 probe resistor should be? also what the capacitance of the low cap probe should be.
P.S. i finally got the varactor diodes for my Sencore CB42. I'll let you know how that turns out.
Sounds good on the CB-42. I will look that information up on the scope. But if you have downloaded the manual it is also in there for the probes. Has all the specs. The original probes are a bit pricey but well worth it.
@@TheRadioShop I posted a video of my sc61 probe build. hope you are well.
Thanks Great teacher.
Thanks you for stopping in.
Enjoyed the video. Thanks. 73 Leo
Thanks
I should add that what I am searching for is 3200uF and 24000uF caps with a tolerance rating of -10%, +75% (HP specs)
You got an easy one Buddy :)
I have a pair of HP 3314A generators on the bench and man... lot's of issues. Usually HP equipment is well designed for repair but these units have everything shoe-horned into a small (1/3 rack?) form factor with some _weird_ inter-board connection solutions. My other HP 8647A was a lot easier to service.
Regarding the small silver/aluminum Sprague axial caps, personally I'm _on the fence_ as to replacing them in my machines right now. I am pretty sure they are hermetically sealed and so should still be good. Will not know for sure until my ESR tester gets here. Are you planning on re-capping those as well? Curious to know what you and others think about that. The same style caps in my two generators currently "under the knife" are now pushing 40 years old...
Cheers,
You have your work cut out for you with them! Good luck Eddy. I will try and give my honest opinion on capacitors. Those silver caps where probably better than anything you can get today. If the ESR is ok, leave them. But with the larger color electrolytic, they have to go. Sort of like the Yaesu FT-101, after all the units I have worked on, I never replace a electrolytic in one because it was bad. Most of the time the owner wanted them replaced. Cannot say that for Kenwood and Icom of that same vintage. HP spared no expense. Thanks for watching.
@@TheRadioShop - Thanks for the info. Yep, I was wary of doing a complete re-cap on them and put that task off. Will test the Sprague caps and if still good (probably) will leave them alone! I have already re-capped the bigger PSU ones, the new replacements are smaller so more free space on the PCB now (and lighter).
I have the issue on one unit mainly sorted (E30/CAL on all ranges) I traced it to a problem in the SYNC circuit which eventually goes into a CPU based frequency counter. Maybe I should do a video vignette on what I find... something to think about.
Cheers and take care now.
Another nice and learning video from you. Keep up the good work. Curious but what type of fuse is that called? Never have seen one before. Thanks.
Those are Littlefuse Micro Series. Thanks
@@TheRadioShop Thank you for the heads up.
New fan and subscriber! Wonderful channel, and I’m looking forward to watching EVERY SINGLE ONE of your videos, and learning as much as possible. May I ask: Have you done a video, or if not, COULD you make a video, or just reply here, talking about how you got to where you are now; how you learned what you know. This FASCINATES me (how people gain their skills), because it reminds me that what one man can do, another can learn. MOST people tell me they’re self taught, and that they just started tinkering, and just did it for years, and now here they are. SOME have been formally trained though, or have military or industrial experience. Even if you’re self-taught though, I’d LOVE to hear about your beginnings and how you got to where you are. Thanks so much! 😊😊😊
Thanks Steve and welcome to the channel. I have not done a video on how I got started, but have mentioned it in several videos. I will put that in the que to do some day soon. And yes, I am self taught, started at the age of 12. Have worked for Curtis Mathis, General Electric, and EF Johnson. Hope you enjoy all those videos and thanks for watching.
i second the motion. good teachers are hard to find.
@@rusty1187 Thanks
You're a genius. Wish I knew half of what you know. And your talent!
Kind of off topic, but do you have any idea what happened to Mikes radio repair? he seems to have just vanished!
I really wished I could answer that.
Read the comments on his last video. Someone talked to him and posted a little of why he left TH-cam.
Bonjour, je viens d'acheter un r&s smg rf generator, j'espere que je n'aurais pas de surprise avec. Je vais de ce pas le brancher. C'est 15 kg plus lourd que l'entrée de gamme siglent et moitié moins cher, j'ai hésité, maintenant que je l'ai, je vais le brancher et on verra bien. 🤔
My kind of repair candidate...
Funny, I had you in mind while I was working on this.