Bottlehead Forum

Bottlehead Kits => Eros Tape => Topic started by: YUL400 on November 23, 2014, 05:20:07 PM

Title: Shunt Regulator A side C4S A end problem
Post by: YUL400 on November 23, 2014, 05:20:07 PM
Hello,
I've just performed Final Voltage Check on the Eros Tape Preamp and Shunt Regulator A side, C4S A end, doesn't light up. OA pad Voltage is 220 volts instead of 170 volts. LEDS are checked. Any idea ?
Thanks.
Title: Re: Shunt Regulator A side C4S A end problem
Post by: Paul Joppa on November 23, 2014, 05:24:51 PM
Does the same voltage appear at the tube socket to which it is connected? If not, check the solder joints. If so, post the rest of the voltages.
Title: Re: A Shunt Regulator A side C4S end problem
Post by: YUL400 on November 23, 2014, 05:46:56 PM
Exactly the same voltage. OA excepted voltages of Shunt Regulator A side C4S are all OK.
Title: Re: Shunt Regulator A side C4S A end problem
Post by: Paul Joppa on November 23, 2014, 07:06:17 PM
The problem is probably not in the voltage regulator board, so we need the rest of the voltages. You can start with the 6922 socket voltages if you like, that has a good chance of leading towards the problem.
Title: Re: Shunt Regulator A side C4S A end problem
Post by: YUL400 on November 24, 2014, 02:59:09 AM
Hello,

6922 voltages at C1=220V, C2=100V, C3=103V, C4=7.7V, C5=0, C6=163V, C7=100V, C8=100V, C9=0

Thanks
Title: Re: Shunt Regulator A side C4S A end problem
Post by: YUL400 on November 25, 2014, 06:49:15 AM
Do you want more readings ?
Title: Re: Shunt Regulator A side C4S A end problem
Post by: Paul Joppa on November 25, 2014, 11:42:04 AM
Do both LEDs on that side fail to light? If so, there is probably a bad solder connection or a reversed LED. You can get more information by measuring the voltage on the LED terminals, but I'd suggest checking visually and re-flowing the LED joints even if they look good. You're going to need magnifier and a strong light!
Title: Re: Shunt Regulator A side C4S A end problem
Post by: YUL400 on November 26, 2014, 04:07:26 AM
I've resoldered both Leds on A end. After I've found one of them melted. They are very fragile components. I've ordered some from Digi-key. Will see with new Leds. I'll keep you updated.

Thanks.
Title: Re: Shunt Regulator A side C4S A end problem
Post by: YUL400 on November 27, 2014, 03:59:23 AM
Problem solved. New diode installed. Many thanks to you Digi-Key Corporation www.digikey.ca for your incredibly fast and professional service. The kind of service excellence that is only found in the aeronautical and / or medical sector. Thumbs up. Thanks to you too Mr Joppa for your help. It's now time for the first try.
Title: Re: Shunt Regulator A side C4S A end problem
Post by: Paul Joppa on November 30, 2014, 01:19:21 PM
"Problem solved" - my favorite two words!

Congratulations, that one was a little tricky. Glad it's working now.  :^)