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Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders. |
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21st Apr 2019, 9:20 pm | #1 |
Retired Dormant Member
Join Date: Oct 2017
Location: Cornwall, UK.
Posts: 2
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Gould 4072 / 4074 Power Supply - please help
Hi all
Thanks to the car boot earlier today, I am now the proud? Owner of a Gould 4072. It was sold as dead, but I couldn't resist it for a fiver ! First of all thanks to everyone who has contributed to previous post about these scopes, they have saved me so much time ( particularly the person who uploaded the PSU schematic, and the valuable tip about tantalum capacitors going short - not something I've come across before. I have now found out my PSU has the 33R feed resistor to Q11 is O/C along with D17 and D18 which are S/C. I suspect this was caused when the tantalum C16 ( I think) went short. Does anyone know what type D17 and D18 are ? I'm guessing fast low current rectifiers but would like to fit the correct parts. Many thanks, Lee |
22nd Apr 2019, 7:29 am | #2 |
Tetrode
Join Date: May 2014
Location: Eichstätt, Germany
Posts: 88
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Re: Gould 4072 / 4074 Power Supply - please help
Hello Lee,
the service manual calls the diodes IS923. Some people suggest that it hast to be a 1S923. Indeed you can find a datasheet for both names. Comparing the specifications leads to the assumption that the two diodes are the same. Greetings, Richard |
22nd Apr 2019, 10:25 am | #3 |
Retired Dormant Member
Join Date: Oct 2017
Location: Cornwall, UK.
Posts: 2
|
Re: Gould 4072 / 4074 Power Supply - please help
Thanks Richard, that's a great help.
I think you are right - 1S923 and IS923 are they same part, but the 1 gets confused for an I Where did you get your service manual ? I've searched online but found nothing complete so far. Thanks again Lee |
22nd Apr 2019, 1:18 pm | #4 |
Tetrode
Join Date: May 2014
Location: Eichstätt, Germany
Posts: 88
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Re: Gould 4072 / 4074 Power Supply - please help
You are welcome!
WME_Bill has a quite good scan of the service manual. Just write him a message! Richard |