New Crack - resistance checks

[rs01]

Ryan,

Since it looks OK measure the resistance out of the circuit.  Yes, others might have been damaged too but let's see if the resistor is bad then move on to the capacitors that would have been molested too.

There should be another resistor between the two caps on the left side of the transformer.  Does it measure as it should?  Again, just measure resistance across it with the amp off.

The good news is the other 270Ohm resistor on 13L to 15L measures out just fine.  The one from 21 to 15 that I removed still shows OL even after removal.

[Paul Birkeland]

I had that happen once, on my first Bottlehead kit actually, the good old Paramour I.  I got a 270 Ohm resistor that was open.

You can pop in a 250-300 Ohm 5 watt resistor if you're in a pinch, or we can mail a replacement.

-PB

[Grainger49]

Ok, now check to see if the capacitors before or after that bad resistor have a bulge at the end of the cylinder.  Often the end pops up when they get molested. 

If the resistor was simply defective nothing should have happened to the capacitors.  If you measure their resistance, a good capacitor simply climbs in resistance.  If that is the case it might just have been a defective resistor.

[rs01]

Paul,

I went ahead and ordered a replacement from Mouser, along with a few LEDs just in case since those seem to be a place a lot of people mess up and have problems from reading (I figured for a few pennies more I might as well have some insurance).  Thanks for all the help.

Grainger,

The three capacitors in the power supply all climb to somewhere around 36-40K Ohm then jump to OL, so I think they're still ok (and there are no bulges or anything).  Thank you as well for all the help and advice - I should hopefully be getting the new resistor in Monday so I'll probably be asking about something else then .

[Grainger49]

That sounds like the caps are good.

[rs01]

Ok, so I got the new resistors in today, put them in, and promptly had a tiny bit of smoke and burnt-out resistor (I'm glad I bought 4).  Obviously this is also what happened to the first one, even though it didn't have any burn marks on the outside .  Any suggestions? 

[Grainger49]

Ok, this means you are drawing too much current.  The two most often reasons are diodes and capacitors in the wrong orientation.  But... if you have looked at this before you might want to have someone else look at the pictures in the manual and your components.  A wife is good for this as they don't have any preconceptions. 

The problem would most likely be downstream of the burned resistor.  That points to everything on the left hand terminal strip.  The "bleeder" resistor could be the wrong value allowing too much current to shunt to ground/circuit common.  All sorts of things could be the problem.  But all connections to the left hand terminal strip need checking. 

Do check that the connections to the two tube sockets are right.  If the outgoing voltage is sent to the wrong tube pin it could cause this problem.

Good luck!  Post back.

[rs01]

Ok, this means you are drawing too much current.  The two most often reasons are diodes and capacitors in the wrong orientation.  But... if you have looked at this before you might want to have someone else look at the pictures in the manual and your components.  A wife is good for this as they don't have any preconceptions. 

The problem would most likely be downstream of the burned resistor.  That points to everything on the left hand terminal strip.  The "bleeder" resistor could be the wrong value allowing too much current to shunt to ground/circuit common.  All sorts of things could be the problem.  But all connections to the left hand terminal strip need checking. 

Do check that the connections to the two tube sockets are right.  If the outgoing voltage is sent to the wrong tube pin it could cause this problem.

Good luck!  Post back.

Grainger,

Thanks, I will re-check all the capacitors and diodes (and dragoon my gf into checking as well).  Just to clarify, by upstream and left hand terminal you're talking about 11-16, correct? 

Thanks,

Ryan

[Grainger49]

If the right hand terminal strip, 1-5, has diodes on it, then I am talking about 11-16.  By downstream, I'm saying that what is drawing the high current happens after terminal 1-5.  There could be a short after those terminals.

[rs01]

If the right hand terminal strip, 1-5, has diodes on it, then I am talking about 11-16.  By downstream, I'm saying that what is drawing the high current happens after terminal 1-5.  There could be a short after those terminals.

I just had the most productive conference call ever - I pulled up a picture of my build and started comparing it to other build pics while bored on a call, and I'm 98% sure I have a capacitor in backwards.  Now I can't wait to get home and check it out!

[Grainger49]

If you have reversed a capacitor it is either bad or going to go bad shortly.  Electrolytic caps don't like a reversed polarity.

[rs01]

If you have reversed a capacitor it is either bad or going to go bad shortly.  Electrolytic caps don't like a reversed polarity.

Would these be an ok replacement? http://www.mouser.com/ProductDetail/Panasonic/EET-ED2E221BA/?qs=%2fha2pyFaduiFjZFkE3tIIGjlXHOgcJUWIOtg08o4sg23Ecmz6BcvkA%3d%3d

After flipping the cap around, the A3 LED lit (A8 did not) and I measured 140v on terminal 1 (90 expected) before shutting it back off because it seemed like the output stage cathode resistors were getting too hot and I did not want to fry them.  I'll investigate more tomorrow, and as always thank you for the help and advice.  There's no way I would be able to do this without the awesome people in this forum.

[Paul Birkeland]

We can send you a replacement cap if needed.

It's good that one of the LED's lit, that's a good start.  I think you can leave the amp on and take the rest of the voltage ratings.

One LED not lighting will present high voltage at either terminal 1 or terminal 5, so don't be alarmed.  With a full rundown of mismatches, we can offer better advice on remedies.

-PB

[rs01]

We can send you a replacement cap if needed.

It's good that one of the LED's lit, that's a good start.  I think you can leave the amp on and take the rest of the voltage ratings.

One LED not lighting will present high voltage at either terminal 1 or terminal 5, so don't be alarmed.  With a full rundown of mismatches, we can offer better advice on remedies.

-PB

PB,

If those caps are ok, I can go ahead and pop one in - I ordered 3 with the extra resistor as a back-up plan in case I'd messed something else up.

Thanks,

Ryan

[Grainger49]

Ryan,

Those are nice caps.  If I understand you either have them in hand or they will be to you soon.  Just to be safe swap out both capacitors on the second terminal strip.  Both saw the high voltage.