New Crack - resistance checks

[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. 

 

[rs01]

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.

Awesome, thank you sir, I'll swap them out this evening.

 

[rs01]

Ok, new caps are in and seem to be working.  I still get one LED lit (a3), but not the other.  Voltages are:

1: 90 145
2: 170 162
3: 0 0
4: 170 162
5: 90 78.3
6: 0 0
7: 100 145
8: 0 0
9: 100 97.1
10: 0 Varies from 0 to around 16v, meter jumps around quite a bit
11: 0 0
12: 0 0
13: 170161
14: 0 0
15: 185 184.2
20: 0 0
21: 206 207

A1: 90 90
A2: 0 0
A3: 1.5 1.5
A4: 0 0
A5: 0 0
A6: 90 145
A7: 0 0
A8: 1.5 13.7
A9: 0 0

B1: 90 145
B2: 170 161
B3: 100 145
B4: 90 77.7
B5: 170 161
B6: 100 96.7
B7: 0 0
B8: 0 0

 

[Paul Birkeland]

Check the solder joints on the LED that goes to A8.

 

[rs01]

Check the solder joints on the LED that goes to A8.

New LED put in and it works!

Awesome!

 

[rs01]

PB, Grainger:

Thank you both so much for your patience and assistance.  The amp sounds absolutely wonderful and I've just ordered the Speedball upgrade - not that I find the amp lacking in any way, but it just looks like fun.

Thanks,

Ryan

 

[Grainger49]

Ryan,

You think, "How can this get any better?"  then get an upgrade and go, "WOW!" 

Enjoy the music!