No.101 - Thandar TG102 Function Generator Repair
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- เผยแพร่เมื่อ 26 พ.ย. 2024
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Found this faulty TG102 on Ebay and couldn't resist it, I love the old school form factor.
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I believe Thandar was formally known as Sinclair Electronics owned by the late Sir Clive Sinclair (RIP). They later merged with Thurbly electronics and became Thurlby Thandar, today known as TTi (Thurlby Thandar International). I recently got one of these off eBay, mine had intermittent output and it turned out to just be dry/cracked joints on the pots.
Thandar was the more industrial side of Sinclair Research, there to make a brand that was UK made, but not associated with the Sinclair consumer side much, though they did make a fair amount of equipment that fitted in the same exact case , with only a front and rear panel change to accomplish this. You can see the back still has the moulded in battery compartment, just the cover is not there.
Many thanks for your video , I have had the same TG102 many years which failed to work yesterday ( used very little these days) while I would have taken the same approach to fault finding , I saw your video however before tackling the job and had the same tant S/C .... Your video saved me a lot of time ... Took away the challenge but saves time . Thankyou for a well produced video . Keith
You are welcome!
I love fixing old gear and making it serviceable again, great job tracking down the problem.
Good move;) Analyzing the circuit lead to the solution. I believe your channel is underrated...
For a YT video I don't see the point in opening the unit up, finding a short circuit and going straight to a tantalum capacitor based on experience.......Thats no fun, no entertainment and no learning experience for my audience!
Thanks for your comments.
Thanks so much for being sooo supportive in the past year, Let's roll on together 2023!🤩 BTW, wish you and your family a big Merry Xmas🥳🥳🥳
Another great video, thanks, cant wait to see what the new year brings
Hi Peter, good to hear from you!.....Yup next year will be much the same as this year I think.....i.e. having a horrible time trying to find faulty test gear to purchase for the channel! All the best for 2023!
Happy new year
Thanks for this my tg102 had exactly the same fault, this video saved me an enormous amount of time and effort, now working fine.
Could not believe it mate..our little TG102 failed to work this week. I know what I'm doing with repairs, but on the off chance, checked if there were any videos for common faults. Your video and the schematic enabled a quick repair. Yep, it was those tantalums again. Both had failed dragging the +/- 14v rails down low. 16V caps on 14v rails ???. Orange horrors. Cheers, Steve (Kent UK)
Couldn't believe my luck. I was working on the exact same fault on the same unit. Busy disconnecting components from the 14v line when I found this video on You Tube. Same cap s/c. Very awkward to get into but replaced it eventually. Working fine now. Realy liked your approach to finding shorts without disconnecting. Thanks
Great to hear my videos have been found useful.😀
That was my first generator back in the mid 80s. Worked very well and would still be a useful device for simple signals.
Great video ian. Another one here with the same fault. Capacitor bit tricky to insert due to sub pcb in the way. Set capacitor legs to correct width using reverse of pcb as a guide then use tweezers to insert. Prepare to curse a few times. Have to agree think a inline fuse should be there for good practice. Transformer thermal will not help if a fault on red power switch develops and probable 13a fuse in mains plug on many units. Mains is only a cm away from sweep input wires and pcb components and also is unshielded so just my preference.
Nice explanation of the repair. Great little unit. Thanks for sharing.
Nice job! Can't believe they didn't manufacture this with a line fuse. Glad you added one.
Normally transformer will have a primary side one shot thermal fuse, especially with any transformer that was specified by RS. So no need for a fuse as the transformer will stop operating if it gets to over 130C.
@@SeanBZA It's curious that this is the first time I've seen a piece of electronic equipment without a primary line fuse. I'm an electronic tech and have seen plenty of designs (as I'm sure you and most of Ian's subscribers are).
@@bubblehead78 TTI, being a UK company, has a 3A fuse in the plug, there to protect the cable from shorts. So no real need to fuse internally, and for overheating failures the primary side thermal fuse is perfectly fine as well, handling all shorts on the secondary, which will only blow the mains fuse on transformer final failure. The thermal fuse, non replaceable, does stop things before the smoke phase, though the smell phase is well on by the time it operates.
That was a fun repair.
I have the matching scope, RS branded, thrown in my junk box - battery tray and cover missing I'm sure and probably not in that great condition, but it does work!
Always love the repair videos!! Thanks
Fantastic repair Ian =D Hope you had a good Christmas and have a Happy New Year!
Great work. Neat "functional' little unit.
Thanks for this video; I learned quite a bit from this video - especially how to effectively look for shorted components!
Its always the capacitors😉. Thanks for the repair video. Best way to learn.
I really need to repair mine! It's a little... unstable 😂 Mine is badged Thandar and I also have the pulse generator and the oscilloscope too (both of which also need some love). They look so cute in a stack!
Stop it....you're making me jealous...:-)
I used to have a Thandar digital multimeter built into the same case. Great devices.
Hi Ian, I have the exact same generator, had it since the mid-nineties. The power button is missing on mine and the exact same cap shorted in front of my eyes (blew a hole 💥in the cap body) as I decided to give it a bit of TLC after years on the shelf! Hope you are having a great Christmas 🎄 break, many thanks for the educational content, all the best for the New Year 🎉
Yes, tants usually destroy themselves spectacularly.....and if you're lucky it'll blow itself off the board completely, and open circuit!
Excellent technique and repair.
I had the Sinclair o'scope and frequency counter back in the 80's.
Love the form factor even after all these years.
Nice one! It’ll be safe from any more sun discolouration up there in Aberdeen!
You're not wrong!
This model has a thermal fuse on the primary, it is fitted between the two right hand terminals on the trans former primary connection.
Sweet! :) Nice work, and I picked up a tip or two. Thanks!
What a great find !.....cheers.
Funny I saw the title and suspected a bad tant. I've found the exact same issue on two I've repaired.
Not the best accuracy wise etc but did the job once
@11:30 It's always a crapacitor Ian....
EDIT: Yep... called it!
You'll have to get to the videos quicker.....there's a couple folks ahead of you in the chat....😀
I never liked Thandar equipment when I worked in the test department, the size of the control knobs was always to small. If your sitting at a bench having to adjust the frequency and amplitude a lot as you do when doing bandwidth tests they gave me cramps in the hand. :-(
Give me a level or hp oscillators any time.
Still nice to see it saved from the WEE bin.
those discrete 5V v
regulator circuits don't look like they'd be very good at temperature or current draw fluctuations? I guess if it's good enough it's good enough...
I had a Sinclair 3½ digits mulitmeter in a similar case and with same gray selector knob.
That was a fun one...😊
Ian as the years almost over what was your most defective componet of the year ?
Gawd knows!.....there's been quite a variety of repairs. Ranging from the bad tant here to the epic Keithley 2001 DMM repair!
Thanks dude
Nice job!
You can't beat a tantalum Cap to be a short ask Scott :-)
Squeak !
@@andymouse Cheesey Short🙂
Yep... I called it!
Back in the day many, including me, thought using tantalum caps was a good choice and so we used them in just about every design, years later all have been proved very wrong.
But they are probably better in failure than the oozy electrolytics that trashed my top of the range Sony head end from 1994. Out of warranty and short of a full replacement pcb totally unrepairable.
Yes, I did a lot of designs with them.....47uF 16v tants on a 15v rail, what was I thinking! We popped a few LOL
Good old tantalum time delayed jumpers.
When you said shorted power supply my first though was tantalum lol. I dont know how many pieces of equipment ive gotten for free that had bad caps
Nice repair! Who would have suspected a shorted tant? I'm surprised - it didn't appear to be discolored - they usually get all black and ugly looking. The transformer must be loosely coupled as I didn't see any overcurrent protection in the power supply. Regards, David
Shorting the +14v rail put the base at the same voltage as the emitter on the main pass transistor and effectively switch off the rail! A good wee design:
Those transformers have very poor regulation, due to the high resistance of the windings, so are almost a pure current source limiting the short circuit current. Short it on the output and it will run for around 20 hours before it finally gets hot enough to melt the primary internal thermal fuse and stop operating. Even if the windings short out internally it will stop once the core gets hot enough.
Nice to see. I have the oscilloscope and the storage unit (which makes it into a storage scope). Both still work.
I have that portable oscilloscope.
Why did you replace the Tantal with Electrolytic Cap? I though Tantal are more reliable, more durable.
Electrolytics when they go they go slowly, so there's a chance to replace without damage. Tants on the other hand they go fast. I've seen many, many PCBs damaged by shorted out tants. I'm just not happy putting them on boards...:-)
hey Ian
Singapore you say?
Early 90's, Jurong Shipyard, on board the new Tam Dao II jackup rig. I had the scope on top of a steel box measuring some electronics inside it, pulled the scope probe lead and hauled the scope off and to the floor.
@@IanScottJohnston Tam Dao 2...That was built for VietSovPetro and didn't even become operational until 2010 from what I have read.
@@douro20mmm, maybe it was Tam Dao I……..I can’t remember.
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