Going through the checkout on my TSE build and all is well until I get to the 5842 portion. While adjusting the plate voltage the R16 332 ohm resister started smoking. I am thinking U2 has failed, the 10M45, how can I test this, not being hip to solid state devices. And what else should I be looking at?
I am going to add to my array of cheap meters today, so I can test more things at once and maybe I can figure it out that way.
tc
I am going to add to my array of cheap meters today, so I can test more things at once and maybe I can figure it out that way.
tc
Thanks for the reply.
R16 was of the correct value- now testing higher now that its cooked- have replaced it. Also checked solder issues- not easy with U2 as it's mounted under the board- may just replace it. Testing voltages across R16 and U2 I am assuming must be done with a 5842 installed?
You may be right about the tube though, I now have one 5842 that won't light up. I am being extra cautious now not knowing where the fault lies. More tubes are on the way.
Without 5842 installed my filament voltage at that socket is over 7 volts, which I reckon I'd see a higher voltage with no load since that's not regulated, still seems on the high side.
Got some disposable meters from Harbor Freight for $3 each, so now can test more things at once. I shelved this project- literally- in a cardboard box and did nothing on audio for over a year, so I'm just now getting my chops back- such as they were.
tc
R16 was of the correct value- now testing higher now that its cooked- have replaced it. Also checked solder issues- not easy with U2 as it's mounted under the board- may just replace it. Testing voltages across R16 and U2 I am assuming must be done with a 5842 installed?
You may be right about the tube though, I now have one 5842 that won't light up. I am being extra cautious now not knowing where the fault lies. More tubes are on the way.
Without 5842 installed my filament voltage at that socket is over 7 volts, which I reckon I'd see a higher voltage with no load since that's not regulated, still seems on the high side.
Got some disposable meters from Harbor Freight for $3 each, so now can test more things at once. I shelved this project- literally- in a cardboard box and did nothing on audio for over a year, so I'm just now getting my chops back- such as they were.
tc
I'm using a nameless surplus transformer- too large for the application actually. I'm having to bring it up on a variac to around 100 volts AC to be in the range I'm shooting for. (My line voltage is at 125 today.) Thinking about buying an Edcor.
Went through a complete testing session on the board today and determined that U2 is indeed dead, will replace that with spares on hand. I went ahead with the testing routine on my good channel and found that the filament voltage starts dropping rapidly after about 2 minutes. It did this with several different 45s and a 300B. No other voltages changed. I intend to use 45s so had the B+ at 320 and set the current at 25 milliamps. Is this the regulator dropping out?
tc
Went through a complete testing session on the board today and determined that U2 is indeed dead, will replace that with spares on hand. I went ahead with the testing routine on my good channel and found that the filament voltage starts dropping rapidly after about 2 minutes. It did this with several different 45s and a 300B. No other voltages changed. I intend to use 45s so had the B+ at 320 and set the current at 25 milliamps. Is this the regulator dropping out?
tc
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