Hello all,
I have a Hickok 539A tube tester with a busted transconductance meter. Exact replacements seem to be very difficult to find, but I’m thinking of replacing the meter with one from another Hickok tester, if I can find one, and swap in the scale from the original meter. This is providing the new meter has the same physical dimensions as the original of course, also as far as the scale is concerned.
Do any of you happen to know of Hickok meters that would fit? And still have the original outer appearance? The manual unfortunately doesn’t mention which type of meter was used. Judging from pictures, the 532 or 600 seem to look alike to me, but I’m not sure.
The replacement meter will probably be less sensitive, but that could be compensated for with a suitable opamp circuit, so that wouldn’t be a dealbreaker.
I’m looking forward to hearing if you have any info on this.
Thanks...
I have a Hickok 539A tube tester with a busted transconductance meter. Exact replacements seem to be very difficult to find, but I’m thinking of replacing the meter with one from another Hickok tester, if I can find one, and swap in the scale from the original meter. This is providing the new meter has the same physical dimensions as the original of course, also as far as the scale is concerned.
Do any of you happen to know of Hickok meters that would fit? And still have the original outer appearance? The manual unfortunately doesn’t mention which type of meter was used. Judging from pictures, the 532 or 600 seem to look alike to me, but I’m not sure.
The replacement meter will probably be less sensitive, but that could be compensated for with a suitable opamp circuit, so that wouldn’t be a dealbreaker.
I’m looking forward to hearing if you have any info on this.
Thanks...
The manual schematic says it's a 97uA, 250 ohms meter. No other info, or even a part number.
Could be an OEM Simpson meter.
https://stevenjohnson.com/hickok/data/hickok-539a-manual.pdf
Could be an OEM Simpson meter.
https://stevenjohnson.com/hickok/data/hickok-539a-manual.pdf
I replaced the meter in my 539c with a meter from these folks - very nice meter.
Alltubetesters.com | Parts
Alltubetesters.com | Parts
If you can get the guy to respond, I guess Alltubetesters is good. I tried for two years to pay him to fix a Hickok tube tester and finally gave up.
Hi guys, thank you for your suggestions. I will definitely keep Alltubetesters in mind, they seem to have the stuff. They are a bit pricey, though, so I would prefer to look at other possibilities first. So, if any of you should happen to know of a meter that has the same mechanical dimensions (both case and movement) as that in a 539A, don’t hesitate to drop a message. A difference on the electric side is not a problem.
Best regards
Best regards
IF---- you are prepared to do some work on it then buy a 100 microamp meter and connect it in circuit with an operation amp to correct for the different current and resistance .
You will need to power it of coarse with a miniature transformer /power supply but that doesn't take up much space.
It will need to be isolated .
I know people in the UK who did this and it works satisfactory.
There is also a circuit out there (UK) to convert an Avo VCM MK4 with a dud meter to a digital display .
The actual meter was selling at £500 but is unobtainable now a replacement (not as good from a UK meter company ) is still £500.
The reason I said it would need to be isolated is that the whole circuit with be at the tube/valve potential so be warned of this.
You will need to power it of coarse with a miniature transformer /power supply but that doesn't take up much space.
It will need to be isolated .
I know people in the UK who did this and it works satisfactory.
There is also a circuit out there (UK) to convert an Avo VCM MK4 with a dud meter to a digital display .
The actual meter was selling at £500 but is unobtainable now a replacement (not as good from a UK meter company ) is still £500.
The reason I said it would need to be isolated is that the whole circuit with be at the tube/valve potential so be warned of this.
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Soundcore-- I got tired of waiting for non-responsive alltubetesters and converted my Tektronix 575 to use the Hickok tube tester sockets to operate similar to a Tektronix 570. You can use a Tektronix 575 or 576 and others.
There is also a paper about how to do this written by Dennis Tillman W7PF, dennis@ridesoft.com
AN INEXPENSIVE VACUUM TUBE CURVE TRACER ADAPTER
FOR ALL TEKTRONIX SEMICONDUCTOR CURVE TRACERS
The file is too big to post here.
AN INEXPENSIVE VACUUM TUBE CURVE TRACER ADAPTER
FOR ALL TEKTRONIX SEMICONDUCTOR CURVE TRACERS
The file is too big to post here.
