hi all.i have a mtx thunder elite 4001d amp on the table with the thermal led on when powered up.
i have checked all the power supply fets and ouput fets all are ok.
any help will be much appreciated.
thank you
i have checked all the power supply fets and ouput fets all are ok.
any help will be much appreciated.
thank you
no there isn't any rail voltage hence no heat.thermal light comes on upon connecting remote there isn't any current draw....just need advice on where to start.
Sounds like the overheat protection circuit is active.
If it uses the same LED for dc protection, it may also have a blown channel output stage.
If it uses the same LED for dc protection, it may also have a blown channel output stage.
ok i still get the thermal light when i apply the remote....here is the readings i have so for using the power ground as reference...
for the tl494
1-0.01
2-5v
3-0.02
4-4.39
5-1.5
6-3.45
7-0.03
8-13.49
9-0.06
10-0.03
11-13.76
12-13.76
13-5
14-5
15-5
16-0.01
there are two lm339 ics i can't determine what the board labels are but this one located toward the fan connection and one towards a +5volt regulator.
for the one towards the fan i get...
1-2.20
2-0.23
3-13.76
4-0.10
5-3.13
6-0.83
7-3.13
8-3.22
9-5.01
10-5.01
11-8.28
12-0.06
13-0.01
14-0.01
for the one next to the +5volt regulator i get...
1-0.21
2-1.53
3-13.75
4-1.56~2.11
5-1.73~2.12
6-1.7
7-0.53
8-2.51
9-0.05
10-0.11
11-1.57
12-0.01
13-3.58
14-0.05
i'm stumped as to why the thermal light comes on when the amp has basically room temperature.i currently have all the power supply mosfets out of the circuit by the way.
any help will be much appreciated thank you.
for the tl494
1-0.01
2-5v
3-0.02
4-4.39
5-1.5
6-3.45
7-0.03
8-13.49
9-0.06
10-0.03
11-13.76
12-13.76
13-5
14-5
15-5
16-0.01
there are two lm339 ics i can't determine what the board labels are but this one located toward the fan connection and one towards a +5volt regulator.
for the one towards the fan i get...
1-2.20
2-0.23
3-13.76
4-0.10
5-3.13
6-0.83
7-3.13
8-3.22
9-5.01
10-5.01
11-8.28
12-0.06
13-0.01
14-0.01
for the one next to the +5volt regulator i get...
1-0.21
2-1.53
3-13.75
4-1.56~2.11
5-1.73~2.12
6-1.7
7-0.53
8-2.51
9-0.05
10-0.11
11-1.57
12-0.01
13-3.58
14-0.05
i'm stumped as to why the thermal light comes on when the amp has basically room temperature.i currently have all the power supply mosfets out of the circuit by the way.
any help will be much appreciated thank you.
ok update everyone i ran into a thread where Perry Babin explains how to disable the protection and i tried that.
with ground and b+ alone connected i get drive signal at the psu mosfets gate resistor.i'll try install the mosfets today and see if i can get audio out.
with ground and b+ alone connected i get drive signal at the psu mosfets gate resistor.i'll try install the mosfets today and see if i can get audio out.
i won't be able to post a picture of the signal as the backlight on my scope is damaged but i know its right because i have a mtx 1000d that had the same wave form and that works fine.
update....i found d210 to be reading short...further checks revealed that it was u203(lm339) that was causing it.replaced that and the amp powers up fine and plays audio.
hope this helps someone in the future.
hope this helps someone in the future.
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