Eros 2 Build [resolved]

[David L Efford]

OK,  I'm a newbie. Finished the build, all volts were spot on along with resistance checks. BUT it sounds awful. I installed the 4 transistors backward on the c4s board and had to remove and reinstall them, was hard to do, so I'm wondering if I got them too hot and burned them. Would that make it sound bad?

 

[Paul Birkeland]

Can you post all the voltages on your small front PC board?

 

[David L Efford]

1A = 218.5
1B = 219.5
OA = 156.3
OB = 160.7
OC = 97.8
OD = 97.2
OKA = 98.1
OKB = 98.0
OKC = 1.54
OKD = 1.72
All 8 - Led's light up.
All readings are VDC

 

[Paul Birkeland]

Can you post some build photos? While your voltages aren't completely out of whack, they also aren't exactly correct, but the operation of both EF86s and the 6922 is a bit suspect, like maybe some resistors on the front PC board got swapped around by accident possibly or something of that nature.  I would not expect this to sound good at all with that set of voltages.

 

[David L Efford]

Paul, Thanks for all the help but I can't seam to get a picture for you, need to fine one of my grandchildren to help me. I get one in the attachments and then it says when I post file to big. How to make the picture smaller???

 

[David L Efford]

Not very sharp, I'll try again hope this is better.

 

[David L Efford]

Who said, you can't teach old dog new tricks. Hope this makes things more clear. Thanks for all your help. DLE

 

[Paul Birkeland]

I would reheat the MJE350 transistors on the front C4S board, with a special focus toward the middle leg of each one.

 

[David L Efford]

Thanks for the reply, I reheated all 4 transitstors on the C4S board, I think I burned them up when I turned them around the first time. there are my volt reading now:
1A - 218.5
1B - 218.9
OA - 157
OB - 161.7
OC - 97.3
OD - 96.6
OKA - 97.5
OKB - 97.4
OKC - 1.483
OKD - 1.536
All readings are VDC

I hooked it back up and know change in sound.

 

[Paul Birkeland]

It wouldn't hurt to try a different 6922.

 

[David L Efford]

What your though on the four transistors on the C4S board. Before I spend money on a vault.

 

[Paul Birkeland]

They appear to be doing what they are supposed to be.

 

[David L Efford]

First I would like to thank Bottlehead for sending me a 6922 tube at no charge, but it didn't fix the problem. Paul where should I look next? Should I take the voltage again?

 

[Paul Birkeland]

Yes, recheck the voltages with the 6922 you've received.

 

[David L Efford]

OK, Here we go again, voltages with new 6922 Tube:
1A - 218.5
1B - 219.1
OA - 155.6
OB - 160.8
OC - 98.0
OD - 97.7
OKA - 98.6
OKB - 98.5
OKC - 1.49
OKD - 1.55
All 8 - LED's Light up
All reading are VDC
Looks like biggest diff. is between OA and OB, but what would that mean?

 

[Paul Birkeland]

Do you have one channel that's now sounding correct?

 

[David L Efford]

Paul, That was good thinking, but No both channel failed. I've started doing a complete rebuild
on paper with a check list. I'm on page 52 now.

 

[David L Efford]

Well I went over everything again and I only found that in a couple of places I used the Lower instead of Upper solder point. would that make a difference. Check out my notes on page 47, item 5, last on the page. My reading on resister was high 48, 60 ohms. Where do I go from here. DLE

 

[Paul Birkeland]

I would reflow the rest of the non-LED solder joints on that center front C4S board.

 

[David L Efford]

OK, PB but this is a stupid question, is it best to remove the C4S board and reflow from the back or careful reflow from the front?