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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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29th Feb 2020, 11:55 am | #1 |
Triode
Join Date: Feb 2020
Location: Sheffield, South Yorkshire, UK.
Posts: 14
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Farnell L30-2
Hello,
I have acquired the above, and the current range does not show an indication, although the voltage is variable, the current limit works and it delivers power to a load. I suspect VT101 - 2N5294, or VT3 - 2N3053. Comments before I open it up? |
29th Feb 2020, 1:03 pm | #2 |
Pentode
Join Date: Mar 2013
Location: Leeds, West Yorkshire, UK.
Posts: 246
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Re: Farnell L30-2
Hi RevGeof,
if the voltage is variable and is present at the O/P the control circuit is ok. I would suspect the switch(if single meter type) and associated current circuit resistors(across the main current sensing resistor) |
29th Feb 2020, 3:57 pm | #3 |
Triode
Join Date: Feb 2020
Location: Sheffield, South Yorkshire, UK.
Posts: 14
|
Hi.
I did wonder about the switch. Is the sense resistor R206? I also forgot to state that the current meter setting pot has no effect. Last edited by Station X; 1st Mar 2020 at 2:54 am. Reason: Posts merged. |
1st Mar 2020, 11:35 am | #4 |
Pentode
Join Date: Mar 2013
Location: Leeds, West Yorkshire, UK.
Posts: 246
|
Re: Farnell L30-2
Yes
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1st Mar 2020, 11:58 am | #5 |
Octode
Join Date: Jun 2013
Location: Huddersfield, West Yorkshire, UK.
Posts: 1,795
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Re: Farnell L30-2
If you have output.. the current sense resistor will be ok..Either the switch or any series resistor FROM the current sense to the meter.
__________________
Should get out more. Regards Wendy G8BZY |
5th Mar 2020, 11:19 pm | #6 |
Triode
Join Date: Feb 2020
Location: Sheffield, South Yorkshire, UK.
Posts: 14
|
Re: Farnell L30-2
Success!
I replaced the bridge rectifier, as C1 was getting hot, suggesting it was passing AC. I replaced C1 in case it was damaged. I also replaced the switch. VT101 was OK, but VT3 was intermittent, also replaced. This seems to have cured the problem. Now to soak test it. Thanks guys! |