Well /diy/ I bought this tube tester/ voltohm meter and all I can find is pictures of it, nothing else. No schematic or anything. Now onto another issue with it, the meter itself vibrates when trying to read the tubes. Could that be because of AC current leaking through a bad filter capacitor?
>bad filter capacitor
Could be open circuit.
There's current going through it, otherwise it wouldn't be spazzing out like it's doing.
>>948730
If it's anything like mine you're going to want to spend a day reworking every solder joint in the thing for starters, ongoing mechanical stress to sockets and switches tends to introduce fractures in the connections over time.
You'll also want to replace every cap in the damn thing. Pull the lids off and show us some guts shots so we can point you in the right direction.
>>948730
http://lmgtfy.com/?q=%22home+n+shop+tube+and+circuit+tester%22
http://www.radiomuseum.org/r/goldprod_home_n_shop_tube_and_circuit_tester_tc101.html
Yes you need to replace all the electrolytic and Paper caps in the tube tester, as well as any resistors that are out of tolerance.
I think it's safe to say that the big yellow one is bad, it looks like an old wax capacitor.
>>948751
I saw that radiomuseum site when I was looking for schematics, but it doesn't really say much other than what's already on the tester itself, it would be amazing if I can find the instruction pamphlet online.
>>948753
replace the yellow cap marked mylar, any cap of the same value and a voltage of 200v or higher can be used. check the resistors and replace any out of tolerance. The bluish grey ones are precision resistors and need to be the value stated. The tan disc capacitor can be left alone.
>>948754
post a question on the antique radio forum or videokarma and someone may have a copy there.
>>948755
Thanks anon
>>948757
Alright.
>>948755
Agreed. That unit is actually in quite nice nick internally though, no signs of living in humid or verminous environs, it would appear it has been taken care of.
I >>948748 wouldn't expect too much to be wrong with it short of the paper caps and maybe some drifty resistors as this guy says.
>>948754
Honestly, its a volt meter circuit with a tube tester added. It shouldn't be too hard to work out a schematic for the VM side of it at least by working back from the input terminals under the selector. Great find OP, definitely feeling some jelly here.
>>948762
Yeah, hopefully I can get it functioning soon.
>>948730
try throwing in a cap to dc couple the meter
>>948755
But mylar caps last forever, why bother?
Would it still work right if I used two caps in parallel? As long as it's the same value? I mean essentially it would be one big capacitor right?
Also, Got a schematic.
>>948834
I'd still replace it, it's not like it would cost a fortune.
>>948834
It has the word Mylar on it but I believe it is still a unreliable wax type.
>>948755
Alright, one of the precision reads 558k Ohms when it's value is 540k, Just to be sure, is the 2% on those resistors tolerance values?
Here are the readings on the Precision Resistors:
Displayed value: | Actual Value:I
540K ohms +/- 2% | 558k ohms |
315K ohms +/- 2% | 318.4k ohms|
540k ohms +/- 2% | 551.5k ohms|
119k ohms +/- 2% | 120.2k ohms|
11k ohms +/- 2% | 10.98 ohms |
3.2k ohms +/- 2% | 3.2k ohms |
43k ohms +/- 2% | 43.16K ohms |
200 ohms +/- 2% | 197.8 ohms |
The "displayed value" is the one printed on the resistor itself. The "Actual value" is the one the ohm meter is reading.
The ceramic cap is reading .02 uF when it's supposed to be reading .01 uF. Replace?
>>949719
The real question is how good is your meter? When was it last calibrated?
Are you sure they are 2%?
>>949758
I've been using a fluke 115 multimeter, I don't know when it was last calibrated. Also, 2% is at the end of each resistance value printed on the resistors, So I'm assuming it's a tolerance value.
>>949719
>Displayed value: | Actual Value:I
>540K ohms +/- 2% | 558k ohms | replace
>315K ohms +/- 2% | 318.4k ohms| keep
>540k ohms +/- 2% | 551.5k ohms| replace
>119k ohms +/- 2% | 120.2k ohms| keep
>11k ohms +/- 2% | 10.98 ohms | keep
>3.2k ohms +/- 2% | 3.2k ohms | keep
>43k ohms +/- 2% | 43.16K ohms | keep
>200 ohms +/- 2% | 197.8 ohms | keep
>>949743
not unless you want to.
>>949802
I'll just leave it.
Anyone know a good place to get precision resistors?
>>951776
mouser
digikey
Thanks
>>948753
old electronics are wonderfull but I hate the way they made everything into a huge clusterfuck of components and miles of wire
>>948754
Join that damn club, it's cheap for what you get.
People on there are very smart and helpful too. I joined and it's great.
