Speedball Voltage readings post upgrade

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Offline [email protected]

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on: May 18, 2019, 06:55:19 AM
I have installed the Speedball and caps with poor results. 
The caps are
Dayton Audio DMPC-100 100uF 250V Polypropylene Capacitor
 
tubes
6AS7 Russian 6H13C tube is also known as 6N13S and 6AS7G.
Genalex - Gold Lion ECC82 / B749

Results

No audio on left side and voltages are off.


Term    correct  My results
1            75   178
2            17   183   
3            0   0
4            170   183
5            75   90
6            0   0
7            100   177
8            0   0
9            100   116
10           0   0
11           0   0
12           0   0
13           170   183
14           0   0
15           185    203
29
19           0   95
20           206   0
A1          75   96
A2          0   0
A3          1.56   1.58
A4          0   0
A5          0   0
A6          75   178
A7          0   0
A8          1.56   0 (led not lit: replaced to no effect)
A9          0   0
B1          75   178
B2          170   183
B3          100   176
B4          75   90
B5          170   183
B6          100   116
B7          0   0
B8          0   0



Offline Paul Birkeland

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Reply #1 on: May 18, 2019, 06:56:50 AM
Can you post some photos of your amp?  (preferably with the stock caps in and not the big monsters that will obscure our view of everything)

In the manual we provide instructions to install the small board then test it before moving on.  Did you pass this test and then run into issues when installing the large PC board?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline [email protected]

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Reply #2 on: May 18, 2019, 08:43:57 AM
hope this helps



Offline Paul Birkeland

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Reply #3 on: May 18, 2019, 03:09:01 PM
Ah, it's an old Speedball!

I would suggest reflowing the solder joints on the MJE350 on the small board feeding terminal 1, especially the center leg.

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline [email protected]

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Reply #4 on: May 18, 2019, 04:36:07 PM
reflowed as instructed.   no effect yet



Offline Paul Birkeland

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Reply #5 on: May 18, 2019, 06:55:18 PM
Can you post some new photos?  What wattage rating is your iron? 

For the MJE350s, your soldering iron is very unlikely to be able to heat them up enough to damage them.  You need to see solder flow through the hole that the lead passes through and wick up a little bit on the other side.  From the original photos you posted, there's no solder coming through on the other end.  For the center lead of the MJE350, it takes a lot of heat to get this going, and without allowing that to happen, the flux inside the solder will create an insulating barrier between the solder joint at the lead of the MJE350.  Once it is hot enough, that flux will be displaced and you will get a proper joint.

This is also consistent with the high voltage you are seeing, and I would bet that one LED on the 9 pin socket isn't glowing anymore either.

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline [email protected]

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Reply #6 on: May 19, 2019, 07:52:05 AM
Hotter is better it seems.  Thank you!

i got my crack back.  Both sides now.

current(hehe) voltages  Unsure about 19, and 20 (21 is 207v)

Term    correct  1st   2nd
1            75   178   91
2            170   183   180
3            0   0   0
4            170   183   186
5            75   90   95
6            0   0   0
7            100   177   114
8            0   0   0
9            100   116   117
10           0   0   0
11           0   0
12           0   0
13           170   183   185
14           0   0
15           185    203   182

19           0   95   96
20           206   0   0
A1          75   96   93
A2          0   0   0
A3          1.56   1.58   1.56
A4          0   0   0
A5          0   0
A6          75   178   92
A7          0   0   0
A8          1.56   0    1.54
A9          0   0   0
B1          75   178   89
B2          170   183   182
B3          100   176   114
B4          75   90   93
B5          170   183   181
B6          100   116   116
B7          0   0   0
B8          0   0   0   



Offline [email protected]

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Reply #7 on: May 19, 2019, 10:32:14 AM
I spoke too soon.


 the left channel is in both ears.  time to do some digging.  do any of the above voltages indicate where I should start?



Offline Paul Birkeland

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Reply #8 on: May 20, 2019, 04:41:21 AM
Your voltages now are looking better.  Having the left channel in both ears is most likely a miswire that will require us looking over some photos to understand what's gone wrong.

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man