Memphis 16-MC1000D Ground Short (Newbie 1st Post)

Here are some pics of the o-scope.
 

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I think the white wire is the drive signal. You can confirm.

Jumping that wire from point to point on the bottom of the board (electrically parallel with the top jumper) may help. On one amp, I used a 22g wire and it helped.

Confirm that you read 0 ohms between the two points before adding the jumper, if you try this.
 
I'll try this out tomorrow.

To clarify when you say to jump the wire on the bottom "electrically parallel with the top jumper" are you saying to run the wire along the same path as the top jumper wire?

Or can I just jump the wire following the shortest path?

I have some 22awg enameled magnet wire. Will this suffice?
 
Hi Perry I added the extra jumper cable and still have overheating.

Question regarding the op-driver boards. Should the components on these boards be identical on both boards?

I can see some aluminum caps and certain transistors are not the same. I understand that when replacing these board transistors, they should be done on both boards rather than replacing once side.

Could this be the cause for the overheating? I'll start logging the components and report back the differences.
 
Correct regardless of the board the same side Q211-Q216 overheats.

Part number on the on the OP-drivers are the same with only the 0405 and 0407 marking being different.

Audio PWM Driver and PS-PWM Driver are different.
Pics attached.
 

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Fets were purchased thru Amazon all the same batch.
Although now I believe the gate resistors may be out of spec.

Correct me if I'm wrong with the color coding.
Resistor 1=Red/Blk/Brown/Gold =200ohms
DMM reading= 10ohms
Resistor 2=Red/Brown/ Yellow/Gold=210k ohms
DMM=50k ohms
 

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I see
1, 0, 0: brown, black, black (0, no multiplier)
1, 0, 4: brown, black, yellow (4, four zeros)

This is on the IRF640s. The 100ks are essentially in parallel (through the gate resistors). Two 100k resistors in parallel will read 50k.

The BP1200 is a similar design and shows the resistors.
http://www.bcae1.com/temp/bp1200p1_sm.pdf

The attached image is from a different memphis 1000. The resistors have a bit better paint job.
 

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Here's are some pics of the readings for the mosfets new and stock.
The new 9640 and 640 seem to be out of spec vs the stock.
3205's look to be within spec of stock.
I was able to determine one of each stock 3205,9640,640 were shorted or reading as a resistor.
The 640 was reading as a resistor.
 

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Hi Perry I understand the meter isn't the best in terms of accuracy.


I've located some replacements for the 9640 and 640.

Mouser has the IRF640NPBF
https://www.mouser.com/ProductDetail/Infineon-IR/IRF640NPBF?qs=9%2BKlkBgLFf3E8kFH1ru13w==
Future has the IRF9640PBF
IRF9640PBF in Tube by Vishay | Mosfets | Future Electronics


Would these be suitable replacements?
Does the difference in Rds(On) in the NPBF and PBF variants of the 640 play any role in deciding which to purchase?

150 mOhms vs 180 mOhms