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Search: Posts Made By: khajr
Forum: Troubleshooting Audio Equipment 11-13-2020, 06:18 PM
Replies: 28
Views: 992
Posted By khajr
Re: troubleshooting definitive technology prosub 60

Hello Finster

I did hit a roadblock. My driver is bad. The first thing I did was perform the resistance check per DT and checked that the driver movement was free without noise/scratching. After...
Forum: Troubleshooting Audio Equipment 10-05-2020, 04:27 PM
Replies: 28
Views: 992
Posted By khajr
Re: troubleshooting definitive technology prosub 60

Hey momaka...Sorry I was referring to the pins for that mosfet. 1 is gate, 2 is drain, and 3 is source.



It only appears that Q4 is warm. I will test as I don't have any spares. I tested R12...
Forum: Troubleshooting Audio Equipment 10-01-2020, 08:49 PM
Replies: 28
Views: 992
Posted By khajr
Re: troubleshooting definitive technology prosub 60

Ya. I have been concerned as well and have been checking trace connections above and below the board.
Forum: Troubleshooting Audio Equipment 10-01-2020, 07:45 PM
Replies: 28
Views: 992
Posted By khajr
Re: troubleshooting definitive technology prosub 60

Attached is an thermal image without the mosfets installed. The second pic has the labels. Not sure if this tells us anything. Took the picture with the sub hooked up with the dimbulb test with a 100...
Forum: Troubleshooting Audio Equipment 09-30-2020, 01:17 PM
Replies: 28
Views: 992
Posted By khajr
Re: troubleshooting definitive technology prosub 60

I did measure voltage going getting to each of the mosfet pins and everything was zero.
Forum: Troubleshooting Audio Equipment 09-30-2020, 11:27 AM
Replies: 28
Views: 992
Posted By khajr
Re: troubleshooting definitive technology prosub 60

I tested to voltage at the connections for the mosfets and found the following:

Q1
P1 and P2 = +169V
P2 and P3 = -169V
P1 and P3 = -300mV

Q7
P1 and P2 = +163V
P2 and P3 = -169V
Forum: Troubleshooting Audio Equipment 09-30-2020, 09:13 AM
Replies: 28
Views: 992
Posted By khajr
Re: troubleshooting definitive technology prosub 60

The new mosfets Q1 and Q7 ought to be here tomorrow or Friday. What is concerning is that I already swapped those out along with C2, C4, R19, D1, and U3. And the it still blew the fuse and R19. Maybe...
Forum: Troubleshooting Audio Equipment 09-30-2020, 08:48 AM
Replies: 28
Views: 992
Posted By khajr
Re: troubleshooting definitive technology prosub 60

Attached is a pic of the board where C1/C2 and C3/C4 are. It looks like you either have C1 and C3 or C2 and C4. Since this is the large case I have C2 and C4.

I am using a 100 watt bulb in the dim...
Forum: Troubleshooting Audio Equipment 09-29-2020, 08:27 PM
Replies: 28
Views: 992
Posted By khajr
Re: troubleshooting definitive technology prosub 60

Thanks for the help momaka. I am waiting on new Q1 and Q7 mosfets to come in. Then I will check those voltages. Yeah...I am trying to be very careful. I took Q1 out and pins 2 (drain) and 3 (source)...
Forum: Troubleshooting Audio Equipment 09-28-2020, 10:11 AM
Replies: 28
Views: 992
Posted By khajr
Re: troubleshooting definitive technology prosub 60

Where should I be measuring the bridge rectifier?
Forum: Troubleshooting Audio Equipment 09-28-2020, 08:18 AM
Replies: 28
Views: 992
Posted By khajr
Re: troubleshooting definitive technology prosub 60

The + and - voltages on the bridge rectifier were off by an order of magnitude and the there was current through the speaker wire.
Forum: Troubleshooting Audio Equipment 09-27-2020, 10:38 PM
Replies: 28
Views: 992
Posted By khajr
Re: troubleshooting definitive technology prosub 60

Yes. It’s Q7. Don’t know why I had Q4 in my head. All three pins on Q1 are shorted together. I will check speaker line voltage and the bridge rectifier. But I am going to guess the speaker line...
Forum: Troubleshooting Audio Equipment 09-27-2020, 08:44 PM
Replies: 28
Views: 992
Posted By khajr
Re: troubleshooting definitive technology prosub 60

Attached is the IR image of the board. Nothing blew. R7 is hot. The camera was set to auto scale temp range based on field of view. so it was 169 degrees F but it got as high as 200 degrees F when...
Forum: Troubleshooting Audio Equipment 09-27-2020, 01:07 PM
Replies: 28
Views: 992
Posted By khajr
Re: troubleshooting definitive technology prosub 60

I don't have a variac so I am going to use the lamp....I had all the parts in my garage to build one. I hope it stays on long enough to get a good thermal image of the board so I can pin point a...
Forum: Troubleshooting Audio Equipment 09-27-2020, 09:05 AM
Replies: 28
Views: 992
Posted By khajr
Re: troubleshooting definitive technology prosub 60

Let me rephrase this...I understand that the bulb is drawing the current but if use a 100 watt bulb will it still be safe enough to leave on long enough to get a good thermal image w/o compromising...
Forum: Troubleshooting Audio Equipment 09-26-2020, 10:26 PM
Replies: 28
Views: 992
Posted By khajr
Re: troubleshooting definitive technology prosub 60

I had to look that up. That is a great idea. I have access to a flir camera can I use this in conjunction with the flir and identify hotspots...or am I supposed to unplug the sub when I notice the...
Forum: Troubleshooting Audio Equipment 09-26-2020, 08:30 PM
Replies: 28
Views: 992
Posted By khajr
Re: troubleshooting definitive technology prosub 60

Thanks BadCaps. The new Q1 and Q7 are shorted source to gate. All pins were shorted on the ones I took out. I did replace U3d and more zener diodes are on order. I will check Q3, Q4, and Q5.
Forum: Troubleshooting Audio Equipment 09-26-2020, 02:11 PM
Replies: 28
Views: 992
Posted By khajr
troubleshooting definitive technology prosub 60

Hello,

My prosub 60 is blowing fuses. I bought replacement 1.25 amp 125v/250v slo blo fuses. When I replace the fuse it blows immediately along with a loud buzzing/hum from the sub. Attached are...
Showing results 1 to 18 of 18

 
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