I have a a/d/s M860 and channels 1 & 2 just quit on me goin down the road, channels 3,4,5,6,7,8 all work fine. The fuse to 1&2 is blown and there are fireworks when I install a new one. I assume there is a dead short some where.
After visually inspecting I dont see any visible damage.
Where do I start to diagnose this issue when nothing is visually blown, and I can't power it up with fuse in channel 1 & 2?
There is alot going on in this amp and it may be beyond my skills, if that is the case are you currently taking amps in for repair?
After visually inspecting I dont see any visible damage.
Where do I start to diagnose this issue when nothing is visually blown, and I can't power it up with fuse in channel 1 & 2?
There is alot going on in this amp and it may be beyond my skills, if that is the case are you currently taking amps in for repair?
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Have you checked all of the output transistors?
Does it blow the fuse with no remote voltage applied?
I've been turning all work away until I get caught up with the work I have now.
Does it blow the fuse with no remote voltage applied?
I've been turning all work away until I get caught up with the work I have now.
I will check the output transistors and try it w/o the remote hooked up and report back.
Thanks again.
Thanks again.
After further inspection I found that two of the four (NDP7060) transistors in the power supply section for channels 1 & 2 are burnt/blown. I will be ordering replacements for all four shortly.
1. Is there anything else I should be checking before ordering parts?
2. What kind of white insulation tape is that used between the transisters/fets and the heatsink?
3. When power supply tranistors fail is it just one of those "Things" that happens with these older amps or is there usually a cause/reason I should be concerned about?
Thanks Matt
1. Is there anything else I should be checking before ordering parts?
2. What kind of white insulation tape is that used between the transisters/fets and the heatsink?
3. When power supply tranistors fail is it just one of those "Things" that happens with these older amps or is there usually a cause/reason I should be concerned about?
Thanks Matt
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Did you check the output transistors for channels 1 and 2?
The tape is probably a ceramic filled silicone material commonly referred to as sil pads.
You can have random failures of transistors but it's generally caused by something else (shorted outputs, shorted rectifiers, shorted transformer...).
The tape is probably a ceramic filled silicone material commonly referred to as sil pads.
You can have random failures of transistors but it's generally caused by something else (shorted outputs, shorted rectifiers, shorted transformer...).
After reading the section on testing output transistors it seems that I need a meter with a Diode test feature. I will have to find a DMM since the only one I have is a old school SENCORE feild effect meter. It does not seem to have the ability to test diodes.
Before you buy a meter, post the make/model here. If you are going to do repair work on car amps, I strongly suggest buying a used Fluke model 10, 11 or 12.
If your meter can read ohms, you can at least determine if any are shorted or leaking badly.
For your meter...
http://www.bcae1.com/temp/meterjig01x.jpg
If your meter can read ohms, you can at least determine if any are shorted or leaking badly.
For your meter...
http://www.bcae1.com/temp/meterjig01x.jpg
I won't be selling any of the ones I have. For car amp troubleshooting, I haven't found a better meter.
If you pay $60, 80, 100 (respectively) for one in good working order that wouldn't be out of line.
If you pay $60, 80, 100 (respectively) for one in good working order that wouldn't be out of line.
There is a good deal on a Fluke 15b locally. I'm sure this will do everything I need, but want to double check first.
Also, do you know what the "Frequency" feature does?
Also, do you know what the "Frequency" feature does?
The frequency measures the frequency of an AC waveform.
I can't recommend it because I have never used one. From what I've read, it's an outsourced meter made by extech that was never meant to be sold in the US. If you look at the various auctions for them on ebay, most of the new ones come from HK or China. I don't like the way my extech meter functions and it would be very undesirable as a bench meter for repairing car amplifiers.
I recommended the specific fluke models for a very specific purpose and they work perfectly for that purpose.
If you want a second meter with more features, something like the 112 is reasonably priced.
I can't recommend it because I have never used one. From what I've read, it's an outsourced meter made by extech that was never meant to be sold in the US. If you look at the various auctions for them on ebay, most of the new ones come from HK or China. I don't like the way my extech meter functions and it would be very undesirable as a bench meter for repairing car amplifiers.
I recommended the specific fluke models for a very specific purpose and they work perfectly for that purpose.
If you want a second meter with more features, something like the 112 is reasonably priced.
Glad I double checked.
This sucks, the fluke 10, 11, 12 are almost impossible to find. Havent found a used one online anywhere (seems that people are hanging on to them). One place still has a few new ones for like $225.
This sucks, the fluke 10, 11, 12 are almost impossible to find. Havent found a used one online anywhere (seems that people are hanging on to them). One place still has a few new ones for like $225.
Ebay generally has at least a couple of them (used). Email me with any auctions that you're interested.
babin_perry@yahoo.com
babin_perry@yahoo.com
Here are a couple that are ending soon. The model 11 has a lil screen damage but looks readable and its cheap cheap.
All the model 10's were north of a $100
FLUKE 112 TRUE RMS MULTIMETER. USED BUT IN PERFECT CONDITION | eBay
Fluke 11 Multimeter without Leads Works | eBay
All the model 10's were north of a $100
FLUKE 112 TRUE RMS MULTIMETER. USED BUT IN PERFECT CONDITION | eBay
Fluke 11 Multimeter without Leads Works | eBay
No problem. Got a fluke 11 for $25 bucks. Should be here in about a week. If it has any issues at least it's returnable.
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You mentioned the fluke 112. Am I wrong in assuming that the 113,115, & 117 will do the same + more than the 112?
There are several locally on craigslist that I can get tomorrow.
There are several locally on craigslist that I can get tomorrow.
I don't have any experience with the others that you listed. Look up the 112 manual on the fluke site. If the others are listed in the same manual, it's likely that they are the same with more features. If they're not listed, look up the other manuals and compare them.
The fluke 12 isn't ideal for repair work but it is a very good meter otherwise. Even if you get one of the ones you listed, continue to try to find the 10, 11 or 12 if you're going to do repair work
The fluke 12 isn't ideal for repair work but it is a very good meter otherwise. Even if you get one of the ones you listed, continue to try to find the 10, 11 or 12 if you're going to do repair work
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