 Posted: Tue Oct 27, 2015 10:48 am Post subject: |
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| That's enough to prove that the AMP board is definitely defective. 12 volt power rail has a low resistance to ground.
Seeing as most parts on AMP board are surface mounted and require a reasonable amount of desoldering/soldering abilities ... next step in this direction would be to start isolating any audio output IC pins that connect to the 12 volt source (3 ICs - 5 pins each). ICs here IF a GOOD replacement board can be obtained, that would be the easiest way to go about curing here for one. I cannot vouch for the emporiums mentioned, nor did I confirm stock. Let me know what you decide. |
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| Posted: Tue Oct 27, 2015 4:12 am Post subject: |
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| I tried the black lead in a few spots the neg pin of c24fl, the gnd pin on c7 plug and the corner screw hole that's earthed. All gave the same readings. | |
| Posted: Mon Oct 26, 2015 3:58 pm Post subject: |
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| You can also put L91 back, if you haven't already. | |
| Posted: Mon Oct 26, 2015 3:55 pm Post subject: |
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3-1 of manual shows disassembly (No.6).
It should have, but from reading reported, seems not to have affected. Where was ground (black meter lead) for this measurement? Sorry - No Edit button (most of the time). |
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| Posted: Mon Oct 26, 2015 3:53 pm Post subject: |
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| 3-1 of manual shows disassembly (No.6).
[quote-"larserik"]I didn't have the amp pcb screwed down would that effect the resistance reading?[/quote] It should have, but from reading reported, seems not to have affected. Where was ground (black meter lead) for this measurement? |
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| Posted: Mon Oct 26, 2015 10:15 am Post subject: |
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| I didn't have the amp pcb screwed down would that effect the resistance reading? | |
| Posted: Mon Oct 26, 2015 10:08 am Post subject: |
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| Ok with U31 reinstalled I measuered the same points again across c32= 4.2-6.0Kohm
Before the 3-3.5Ohm That was measured that with the connector J7/MCON12 disconnected as I thought it may have damaged it getting the board to where I could test it. With the connector J7/MCON12 connected the reading on the same points was 2.9Ohm |
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| Posted: Mon Oct 26, 2015 9:49 am Post subject: |
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| Reinstall U31.
Disconnect other amp connector J7/MCON12. Repeat resistance measurements to SAME 2 points. |
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| Posted: Mon Oct 26, 2015 9:20 am Post subject: |
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| Sorry my mistake, it's 3-3.5 ohm from that wire to ground on the amp pcb | |
| Posted: Mon Oct 26, 2015 8:44 am Post subject: |
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| I am NOT asking whether the wire that carries 12V from the power supply to the amp board has continuity.
I'm asking if there is a low ohm reading from that wire to GND. |
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