Brings back memories. As a kid, I remember getting a Heathkit AM/FM tabletop radio kit in the 1960's and built it when I was about 12 y.o. What a great time to grow up in. I graduated from a trade tech school too, in Connecticut in 1973. Life was so much simpler then.
Good on ya that you didn’t edit out getting shocked, it’s easy to make a small mistake and get bit (speaking from experience)… a reminder to all of us that electricity is unforgiving of mistakes.
My strategy about that capacitor in a similar instrument was "just take 4 CBB21 630V capacitors, put them in series and triple heatshrink the whole assembly, then run an insulation tester on it"....
Thanks for the suggestion but one way or another I'm going to have to place an order. It appears that it is only in circuit during AC measurements and I would probably never measure AC voltages over 1000 volts (that's what I have a capacitor for) but if it finds its way to another user it could cause a problem. Thanks for commenting, I always enjoy responding.
The meter was surprisingly clean inside compared to how filthy it was outside. I’m not sure why but vintage HeathKit stuff is through the roof right now on eBay. Fred- What kind of maniac doesn’t love old multimeters?! 😂👍
Most V.T.V.M.s were designed to be used in the upright position, any other position wold cause problems from the heat of the tube(s). Yes I have several (no Heath) on my bench. Ran a B & K 177 at the stereo repair shop until it closed in 2000. Thanks for the video.
I applaud your willingness to learn. Generally speaking it is not a good idea to install wrong value parts as you are re-engineering the circuit. Heath did have a nasty habit of using the wrong value of components on some equipment.
Nothing compared with what you are up against with some russian meters, eg the Z4324 (not a VTVM) - they specified no precision resistors, instead they put two resistor footprints in series (often NOT in the same spot on the board!) and told you in the manual to put two resistors in that gave a total value of XYZ with a ridiculously low tolerance. 1940s meters with mostly handwound resistors, often unmarked, and many versions (and if there is a component layout plan at all, it is for a slightly different version) are also fun to work on :)
You should not run capacitors in series to gain voltage rating. It will work for a while, but eventually the creep and leakage will cause one of the capacitors to be over-voltaged and cause faster degradation. This can be seen via leakage through the stack. Most caps are overdesigned anyway, usually at least 50% over, and sometimes x2, so this will work for a while. Usually the series stack will fail during fast charge, or fast discharge, where one overwhelms the other. We did pulse work, and this is common, even if they have resistor balancing circuits around them. If you are going to series, always use the voltage rating as thought there were only one, for each.
Thank you. I usually don't do that but in this circumstance it's only only used in the AC circuit and I would never use this meter for 1500 volts. But since I have to place an order anyway my plan is to order the correct capacitor.
I redid one of these. It was fine untill I found out the 1% resistors had gone up in resistance. to my knowledge these are not available any more. Does anyone know differently.
I believe you can get the resistors from either DigiKey or Mouser.( Not cheap) I have some that I need to replace myself. Since I will primarily be using it on DC, those are the only ones I'm really concerned about replacing.
Brings back memories. As a kid, I remember getting a Heathkit AM/FM tabletop radio kit in the 1960's and built it when I was about 12 y.o. What a great time to grow up in. I graduated from a trade tech school too, in Connecticut in 1973. Life was so much simpler then.
Thanks for responding, I can truly relate to what you said especially about simpler times
17:13 Nice shot! Lets wonder what's happening for the next 3 and a half minutes.😂😂😂😂 !!!!
Good on ya that you didn’t edit out getting shocked, it’s easy to make a small mistake and get bit (speaking from experience)… a reminder to all of us that electricity is unforgiving of mistakes.
Mistakes like that happen when you don't feel good and aren't fully engaged in what you're doing. Sorry for the crappy filming.
My strategy about that capacitor in a similar instrument was "just take 4 CBB21 630V capacitors, put them in series and triple heatshrink the whole assembly, then run an insulation tester on it"....
Thanks for the suggestion but one way or another I'm going to have to place an order.
It appears that it is only in circuit during AC measurements and I would probably never measure AC voltages over 1000 volts (that's what I have a capacitor for) but if it finds its way to another user it could cause a problem.
Thanks for commenting, I always enjoy responding.
The meter was surprisingly clean inside compared to how filthy it was outside. I’m not sure why but vintage HeathKit stuff is through the roof right now on eBay. Fred- What kind of maniac doesn’t love old multimeters?! 😂👍
Most V.T.V.M.s were designed to be used in the upright position, any other position wold cause problems from the heat of the tube(s). Yes I have several (no Heath) on my bench. Ran a B & K 177 at the stereo repair shop until it closed in 2000. Thanks for the video.
Thanks and yes they need to be vertical, I have 2 Eico, 1 of which I converted to IC's instead of tubes so it runs on 2, 9 volt batteries.
I applaud your willingness to learn. Generally speaking it is not a good idea to install wrong value parts as you are re-engineering the circuit. Heath did have a nasty habit of using the wrong value of components on some equipment.
Nothing compared with what you are up against with some russian meters, eg the Z4324 (not a VTVM) - they specified no precision resistors, instead they put two resistor footprints in series (often NOT in the same spot on the board!) and told you in the manual to put two resistors in that gave a total value of XYZ with a ridiculously low tolerance. 1940s meters with mostly handwound resistors, often unmarked, and many versions (and if there is a component layout plan at all, it is for a slightly different version) are also fun to work on :)
You should not run capacitors in series to gain voltage rating. It will work for a while, but eventually the creep and leakage will cause one of the capacitors to be over-voltaged and cause faster degradation. This can be seen via leakage through the stack. Most caps are overdesigned anyway, usually at least 50% over, and sometimes x2, so this will work for a while. Usually the series stack will fail during fast charge, or fast discharge, where one overwhelms the other. We did pulse work, and this is common, even if they have resistor balancing circuits around them. If you are going to series, always use the voltage rating as thought there were only one, for each.
Thank you. I usually don't do that but in this circumstance it's only only used in the AC circuit and I would never use this meter for 1500 volts.
But since I have to place an order anyway my plan is to order the correct capacitor.
Move your Lamp!
I redid one of these. It was fine untill I found out the 1% resistors had gone up in resistance. to my knowledge these are not available any more. Does anyone know differently.
I believe you can get the resistors from either DigiKey or Mouser.( Not cheap)
I have some that I need to replace myself. Since I will primarily be using it on DC, those are the only ones I'm really concerned about replacing.
You should watch your own video before publishing it. Just sayin'
I hear you, my only response is that I shouldn't do videos when I'm not feeling well. Sorry for the crappy filming.