Shunt Regulator 1/2 working [resolved]

Eugen_syd · 3190

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Offline Eugen_syd

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on: April 21, 2019, 12:30:49 AM

My name is Eugen and I am from Sydney Australia. I am building an EROS Tape Amplifier for a customer of yours named Viren. I am following your instruction step by step. I stopped on page 58 at Shunt regulator voltage test where I can see just side A of the Shunt Regulator LED's light up. I read the other postings about the fault finding and everything I tried does not take me any further. I heat up the legs of the MJ5731A Transistors and took this board off about 3 times. I can not find anything wrong with it however side A give me a bit over 220VDC where side B is over 300VDC. Any suggestions? Should I take the board again off?
BTW, these wires were intended to be this stiff? I never built anything on tube so I do not know much about this area!
Hope to hear form you soon.
Best regards from Down under,
« Last Edit: April 21, 2019, 04:44:37 AM by Paul Birkeland »

Offline Eugen_syd

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Reply #1 on: April 21, 2019, 12:42:39 AM
Hi again,

please do not worry about my message. I just read the posting after me and noticed that I did not connect on D4 with D5. let me rectify this and get back to you.
Rules of support:
1. Give him one day he will figure it out....
2. Make him write it down... 75% will find the answer....
3. Leave the response for tomorrow... maybe tomorrow you do not have to worry about... :)
Just some dry jokes......


Offline Eugen_syd

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Reply #2 on: April 21, 2019, 01:09:02 AM
Houston, we do not have a problem.. :) As usual the problem is us the customers. I should have applied the 4th rule of support! RTFM!!!! read the F***king Manual. Yes pin D4 was not connected with pin D5 so just half of the 12BH7 was fired up. I conected pin D4 with pin D5 and all is good, I get the voltage regulated to 220-ish VDC on both channels A and B. Moving to page 59...


Offline Doc B.

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Reply #3 on: April 21, 2019, 04:06:55 AM
Well done! Working through this stuff and solving it yourself always adds to the satisfaction. We do watch the forum but on weekends it can take a bit longer to reply, particularly for me. Race season is fast approaching and I am pretty much focused on the preparation for that for the next few months of weekends.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.