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Old 11th Nov 2018, 7:17 am   #1
jomac_uk
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Question Vintage Heathkit TC-2 Valve Tester

I have recently bought a 1959 Heathkit TC-2 valve tester for just under 30 to sort through my growing collection of (1000+) valves. I've bought it as a tool and not for restoration, so I'm not too concerned about modifying it.

I've not had a valve tester before, so this is a learning curve and I realise it's not going to be anywhere as good as an AVO or a Mullard etc. My question is for the more experienced amongst us, what mods could I do to make this piece of equipment more useful apart from adding a few more bases etc?
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Old 11th Nov 2018, 11:20 am   #2
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Default Re: Vintage Heathkit TC-2 Valve Tester

I would replace the capacitor and rectifier, check the resistors and fit a 1 Amp fuse in the mains socket.

Then test it with a cheap valve to see if there are any problems. Bad contacts and faulty switches may then become apparent.

It would be a good idea to create a calibration valve of known gm using a simple test circuit so that you could check the accuracy of the Heathkit.
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Old 11th Nov 2018, 5:17 pm   #3
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Default Re: Vintage Heathkit TC-2 Valve Tester

I have a TC-1 and two TC-2 testers and in none of them have I needed to replace the rectifier. Since they use a copper-oxide rectifier it can't easily be replaced with a standard silicon rectifier diode (1N4007 etc.) because of different characteristics for the forward voltage drop. The rectifier is used btw only when doing the adjust-line calibration. Besides, I have yet to come by a defective copper-oxide rectifier at all; they last forever.
In all of the testers most resistors were quite off specifications and the 0.1uF capacitors for the leakage/short test function were themselves leaky.
The TC-2 is an emission-tester that can't measure Gm but that isn't terribly important if you just need to sort valves in bad and (probably) good piles.
When a TC-2 finds a valve Good it may still be faulty. You need a better tester for effectively finding valves with grid-1 current problems.
A fairly inexpensive vintage B&K 667 (or 607) tester or the like will do it nicely.

Last edited by tri-comp; 11th Nov 2018 at 5:24 pm.
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Old 11th Nov 2018, 7:15 pm   #4
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Default

Quote:
Originally Posted by Silicon View Post
I would replace the capacitor and rectifier, check the resistors and fit a 1 Amp fuse in the mains socket.

Then test it with a cheap valve to see if there are any problems. Bad contacts and faulty switches may then become apparent.

It would be a good idea to create a calibration valve of known gm using a simple test circuit so that you could check the accuracy of the Heathkit.
I had fully intended to check all resistors and replace where necessary, and simply replace the caps anyway as a matter of procedure before even switching on for the first time. I was looking to add and modify this tester to further enhance its usefulness, and it's ideas for this I am looking for.

Quote:
Originally Posted by tri-comp View Post
I have a TC-1 and two TC-2 testers and in none of them have I needed to replace the rectifier. Since they use a copper-oxide rectifier it can't easily be replaced with a standard silicon rectifier diode (1N4007 etc.) because of different characteristics for the forward voltage drop. The rectifier is used btw only when doing the adjust-line calibration. Besides, I have yet to come by a defective copper-oxide rectifier at all; they last forever.
In all of the testers most resistors were quite off specifications and the 0.1uF capacitors for the leakage/short test function were themselves leaky.
The TC-2 is an emission-tester that can't measure Gm but that isn't terribly important if you just need to sort valves in bad and (probably) good piles.
When a TC-2 finds a valve Good it may still be faulty. You need a better tester for effectively finding valves with grid-1 current problems.
A fairly inexpensive vintage B&K 667 (or 607) tester or the like will do it nicely.
I'm probably looking to end up with a tester that does something slightly more useful than a Go/No go service, but not anywhere as advanced as some of the bigger testers Iv'e seen. I don't mind doing some hacking and modding to the unit, I want to end up with a tester that gives me a valve that is says is good and I stand a fairly good chance of finding it is.
Some of the valves I have are vintage TV valves, ie PY500's, PL504' 509's etc and I want a reasonable chance of testing these as well.
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Old 11th Nov 2018, 9:02 pm   #5
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Default Re: Vintage Heathkit TC-2 Valve Tester

If you want to show that valves are good you're going to have to be able to test gm.

It would require extensive mods to this tester to do that. I suggest you buy or build a better tester.
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Old 12th Nov 2018, 11:52 am   #6
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Default Re: Vintage Heathkit TC-2 Valve Tester

Hello jomac,
With over a 1000 valves to test, as Graham says, you'll eventually will need to think about a more advanced tester. One that can display Ia, whilst monitoring the correct -ve Vg. Particularly if your collection contains valuable valves such as ECC83's, EL &/or KT O/P valves, or very old PX valves, and so on.
PM me your address & I'll send you a DC Standardised valve for testing your Heathkit tester, buck sheesh.
But hey, you & Graham both live in Ipswich, so perhaps he could recommend someone local with an AVO VCM or similar, & who could possibly kindly also check how accurate/reliable your TC-2 is ?
I ken sfa about TC-2's, but do they require test cards ? You might also need some alternative source of valve data, such as the vintage Bernards & Illiffe Valve Data Books(( see adjacent recent thread).

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Old 12th Nov 2018, 1:38 pm   #7
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Default Re: Vintage Heathkit TC-2 Valve Tester

The Mullard is pretty much a go/no-go tester and needs a huge stash of cards to make it work.
The Heathkit isn't much better but at least it's switchable so you don't need the cards.
An AVO will be overkill and will require a visit to the Bank Manager for a small mortgage to buy one.

If you want better than the Heathkit, I can't recommend the Sussex highly enough, look on this forum for full details. There are quite a lot in existence now, and they have lots of functionality for not a lot of cost.
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Old 13th Nov 2018, 12:32 am   #8
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Default Re: Vintage Heathkit TC-2 Valve Tester

I have learned a lot from the comments guys, you have overloaded my brain with thinking, but I now realise that the best thing for the Heathkit is a renovation and sell on.

During this time, i haven't sat around, and kept looking for a solution to testing the valves I have, and maybe more in the future.

During my travels, and some reading, I found this, not cheap, but claims to do most things. Would this be an interesting thing to consider?

http://www.dos4ever.com/uTracer3/uTracer3_pag0.html
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Old 13th Nov 2018, 7:46 am   #9
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Default Re: Vintage Heathkit TC-2 Valve Tester

I have looked at that one, it seems well designed but it has too many features for my needs. I believe that the user interface needs a Windows computer which I don’t own. I use the Sussex at work to check and match valves for guitar amplifiers, I rarely need to do a full set of curves for a valve.
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Old 13th Nov 2018, 11:27 am   #10
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Default Re: Vintage Heathkit TC-2 Valve Tester

Aye jomac, you say that that u Tracer is not "cheap", but what does it actually cost ? Certainly, if you envisage becoming involved with serious amplifier design or advanced valve circuitry, then you would need to study a valve's family of characteristic curves. I can't remember if anyone has put a price on a Tek, or Roetest, but I suspect that they cost as much as CT160's or VCM163's are now fetching(silly eBay prices of 1000 plus)!
If you just want to plod on with normal vintage radio pursuits, then an AVO VCM Mk1 or 2, or a Taylor 45 would suffice. You're still talking 150 to 300, depending on condition. I've heard that Mk's 3 & 4's are now being internet wheeled & dealed at 300 - 400 plus. If you've got the electronics skills, then the Sussex would be a worthwhile option. Hey - has anyone actually put a finished price on one ? Lets not forget the Hickok range of testers. American 110V yes, but highly thought of. Then myself & one or two other Forum folk have banged-on about building homebrew DC valve testers, but I shant go there.

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Old 13th Nov 2018, 12:13 pm   #11
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Default Re: Vintage Heathkit TC-2 Valve Tester

Quote:
Aye jomac, you say that that u Tracer is not "cheap", but what does it actually cost ? Certainly, if you envisage becoming involved with serious amplifier design or advanced valve circuitry, then you would need to study a valve's family of characteristic curves.
Its approx 187 but it does give you the facility of looking at the curves and even printing them out. I recently purchased a large quantity of vintage valves, many of them extremely rare Cossor's dating back to the 1920's These i plan to test and sell on, but to realise the full value, a decent test with printed results would help very much.
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Old 13th Nov 2018, 2:30 pm   #12
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Default Re: Vintage Heathkit TC-2 Valve Tester

Well jomac, I'm now in a quandary. On the one hand, I've had a fair bit of recent experience in testing early & very valuable 1920's valves for a BVWS chum who is into early vintage radio restoration. On the other hand - there is yourself who seems to intend just dealing valves as a business, as opposed to the ethos of this vintage radio repair & restoration forum.
So - I'm out of this thread.

Comments Moderators ?

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Old 13th Nov 2018, 4:42 pm   #13
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Default Re: Vintage Heathkit TC-2 Valve Tester

No, perhaps i misworded it David. I have a large collection of valves, many of them are either duplicates, or valves of no interest, it's these i intend to sell on, and fund's used to buy more for the collection, simple as that.!
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