Help with an amp, turns on but no sound

[HeavyD'sCustom]

OK dont remember where i got the amp from, but its a precision audio hsp-400.
And the power light comes on, but no sound at all, and it doesnt smell burnt or look burnt, overall it looks fine.
And does not draw any amps, does not blow fuses, even with the fuse out the power light still comes on.

Just need help to see if its worth my time to fix or just take parts from.

I do have other amps - 1 4ch*200/ch works great.
- 1 2ch sony small but works great.

So its not necessary

[Perry Babin]

Can you post a photo of the inside of the amp?

[HeavyD'sCustom]

OK here is a pic

[HeavyD'sCustom]

OK here is another pic.

Oh is there a way to post more than i pica at a time?

Thanx D

[audioDIYer]

Originally posted by HeavyD'sCustom
Oh is there a way to post more than i pica at a time?

Using one of the free image hosting like flickr or photobucket.... And use the "IMG" button when editing your post

[Perry Babin]

With the amp powered up, measure (and post) the DC voltage on the center legs of the large transistors. Place the black meter probe on one of the non-bridging speaker terminals. Two transistors should have positive voltage and two should have negative voltage.

[HeavyD'sCustom]

Originally posted by Perry Babin
With the amp powered up, measure (and post) the DC voltage on the center legs of the large transistors. Place the black meter probe on one of the non-bridging speaker terminals. Two transistors should have positive voltage and two should have negative voltage.

OK did what u asked and two were .35 volts and the other had none.

Does it matter I already took one out before the test?
If u look at the pic its not there. But according to testing the D718 transitor is ok (the one I took out).

[Perry Babin]

In the first photo, the 4 transistors on the left, measure the DC voltage (black probe on chassis ground terminal, amp powered up). If the voltage is the same for all 4 transistors, you only need to post one set of voltages. Copy and paste the following:


Pin 1:
Pin 2:
Pin 3:

[HeavyD'sCustom]

Originally posted by Perry Babin
In the first photo, the 4 transistors on the left, measure the DC voltage (black probe on chassis ground terminal, amp powered up). If the voltage is the same for all 4 transistors, you only need to post one set of voltages. Copy and paste the following:


Pin 1:
Pin 2:
Pin 3:

the first two:
Pin 1: 0.3
Pin 2: 1.0
Pin 3: 0.0

the second two:

Pin 1: 0.04
Pin 2: 0.4
Pin 3: 0.04

[Perry Babin]

Are you sure the fuse isn't blown?

If not, you probably have a broken solder connection between the B+ connector and the power transformer. The inductor is a prime suspect.