6A8G.
Society Members
Hard working kiwi soundmixer.
Posts: 69
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Post by 6A8G. on Sept 19, 2021 12:21:40 GMT 12
Hello there my latest Heathkit rebuild is the CS-1 Capacitor Substitution box. It was quite cheap too... & I expected the worst. Apart from the smallest caps they were all leaky! Pity - I always thought the "Black beauty" capacitors were beautiful. Here's me testing one of them on my C-3 tester...
& the eye closed on the lowest (25V) setting. Never mind, nobody expects capacitors to last for ever... Here's my rebuild - caps are probably better tolerance & no leaks. On a whim I tried carried out a leakage test between the front terminals & the case. There was leakage here too - albeit very small. I unscrewed the terminals & gave them a spin in the sonic bath. The washers are made of fiber material so I just massaged them with a soft cloth. After reassembly there's no leaks to the case either.
Heathkit gear is great:) best... John.
Monday update, the caps are not Black Beauties, they're Bumblebee caps. Still unreliable after 70-odd years though!
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peter
Tinkerer
Retired, collector of vintage radios and test equipment for restoration and repair.
Posts: 97
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Post by peter on Oct 7, 2021 3:32:41 GMT 12
Me too - I've been collecting the Heathkit test gear for years. At the moment I've got a sine square wave generator (see other thread) of theirs that is driving me bonkers. When I got it (off trademe) it was producing lovely sine and square wave outputs whose amplitude was pulsing up and down. Thinking this was the power supply I replaced it's electrolytic caps, a high resistor and based on a you tube video diagnosis the voltage regulator transistor. So all is fine regulated rock steady power supply voltage. Still fluctuates in amplitude - three electrolytics on the main board so replaced those - could not find 250uF caps so used 220uF and the .680uf had to be 50vw (not 35) but these should not affect things noticibly.
Still fluctuating so carried out setup as per manual adjusting preset pots etc. Now have beautiful non- amplitude fluctuating sine wave of correct voltage and frequency - and a distorted square wave! Sigh!!! Suspect I might have either a dicky symmetary preset or a resistor gone high.
Have a lovely Heathkit VTM as well which is likewise driving me to the point of almost totally stripping the main board and rebuilding according to the manual - replaced all the obvious things from resistors, capacitors through to valve but the darned thing will NOT balance despite the voltages being OK on the valve base. Will be something dead simple no doubt. Great fun though and a wonderful feeling when you do eventually track the fault down.
Lots of Heathkit projects as well - for example have to recap a 'scope (the same one as on Mr Carlson's internet lab pages), but it is currently working, as well as make some coils for one of their Grid Dip meters - have about 5 of those so can copy a full set. Then there is a DVM that is defunct waiting in the wings. Finally if I get time I'll replace the eletrolytic I missed when doing the others in the audio section of their shortwave radio - might also prod around a bit as it's performance is less than startling.
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6A8G.
Society Members
Hard working kiwi soundmixer.
Posts: 69
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Post by 6A8G. on Oct 10, 2021 8:50:09 GMT 12
I know it might be a bit obvious but did you try replacing the valves in the generator?
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Post by Peter Walsham on Oct 10, 2021 9:02:21 GMT 12
Peter's signal generator is a fully solid state unit
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peter
Tinkerer
Retired, collector of vintage radios and test equipment for restoration and repair.
Posts: 97
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Post by peter on Oct 10, 2021 14:37:10 GMT 12
Peter's signal generator is a fully solid state unit Thanks to both of you for the suggestions - BUT there is a lamp unit in it which I presume has a filament - although the square wave was perfectly fine (but like the sine with varying amplitude) before I fiddled with things/replaced caps etc. - so it's there but something is out of whack as it's distorted. Sine as I said before is find and healthy in shape and frequency as the scope shows. In one sense it's not a problem as I very rarely use square waves and have a special unit I built years ago for creating them. It's just the uncomfortable feeling something may be on the way out!!
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