Jenny Reloaded problem :(

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2 years 6 months ago #7149 by Pacman223

lcc wrote: HI
i know that your clock has being running ok for some time
i can remember when i built one of these clocks i had trouble with the super cap it was solders to close to the board and solder had built up under neath it and shorted out stopping the clock from working just thought i would mention it just in case you had the same problem and it has only just started to give you trouble


Thank you for your input.. I wiggled the super cap further away from the board, and removed as much solder as possible, didn't have any effect. but I really appreciate your input, Thank you

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2 years 6 months ago - 2 years 6 months ago #7150 by Mr.Nixie
The ceramic disk are "normally" specified for 50 VDC but during the last time it looks that one batch of this types will fail (short circuit) after a long time of operation near to their voltage limits (47 VDC).
If t2 runs hot even with the replacemenr part it can happen that also C20 is faulty as it is also connected to the HV rail.
BTW: the clock will work even without C13 / C20.
If this will also not help unsolder the jumper H/I to disconnect the Gate of the MosFet from the PIC's PWM stage and see what happens than. I have also had a few PICs which has a continuously "high" on pin 13 instead of a regulated 50 kHz PWM signal. This "high" will cause nearly to "grill" the MosFet. Than you need to order a replacement PIC.
Last Edit: 2 years 6 months ago by Mr.Nixie.

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2 years 6 months ago #7151 by Pacman223
Juergen,

thank you very much for your suggestions. I'll take your suggestions and report back.

I'm ordering a IV-13 clock soon, I might ask for a new jenny Re-loaded pic chip to be inlcuded :) if I think it will help.

Thanks

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2 years 6 months ago #7152 by Mr.Nixie
No problem at all.
I am not sure if you have an osci. If yes unsolder the H/I jumper as described before and put the probe on pin 13 of the PIC. You should get a square wave signal of around 50 kHz with a duty cycle of 80 %. If you get a constant high, than the PIC is faulty.

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2 years 6 months ago #7153 by Ty_Eeberfest
I can sort of explain the 1.7K reading. Note that one end of R4 goes directly (same node) as the HV test point. You read about 0.7K from test point to ground. Other end of R4 goes thru 1K to ground. 1K + 0.7K = 1.7K.

So I think that mystery is solved and the reading is just a distraction from the real problem. The real problem being: why do you see 0.7K to ground at the test point?? Seems way too low a reading to me. Maybe time to look at C20 as Juergen mentioned. I didn't even notice C20 over there until I read his post.

Removing jumper H-I and scoping the PWM sounds interesting and I'd like to hear what you find.

Look into it later when the dust is clearing off the crater.

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2 years 6 months ago #7156 by Ty_Eeberfest
So what ever happened with this?

Look into it later when the dust is clearing off the crater.

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