Team Cactus 7kw

Perry Babin · 2011-01-03 10:38 am

What's the circuit board designation of the 7915?

mike49504 · 2011-01-03 10:45 am

Ok out of the amp this is the readings i get on the regulators

7905
1-2:0.548
1-3:0.704
2-3:OL

Probes reversed

1-2:OL
1-3:1.120
2-3:0.551

7805
1-2:0.550
1-3:0.577
2-3:0.914

Probes reversed

1-2:OL
1-3:OL
2-3:0.606

7815
1-2:0.556
1-3:0.570
2-3:OL

probes reversed
1-2:OL
1-3:OL
2-3:0.617

7915
1-2:0.539
1-3:0.716
2-3:OL

Probes reversed
1-2:OL
1-3:OL
2-3:0.532

Do any of theese so far appear to be defective?

Perry Babin · 2011-01-03 10:57 am

I don't think you can determine much this way unless they're shorted or leaking badly.

What's the circuit board designation of the 7915 you originally measured the voltage on?

mike49504 · 2011-01-03 11:00 am

U10

I have to do some checking into this amp now . Now the power light doesnt light up but relays kick on same problem as the other amp i worked on.

Perry Babin · 2011-01-03 11:06 am

When you finish, if you haven't found the problem, find D26-D29, L11 and L12. Do you have DC voltage on both ends of L12?

mike49504 · 2011-01-03 11:15 am

I need one of theese Can i replace them with a mylar cap (104) or do you know a good part number for theese?

Perry Babin · 2011-01-03 11:21 am

Which capacitor?

Was it shorted?

mike49504 · 2011-01-03 11:35 am

Its at the end of the board in front of the 7915 I circled it a lil better now

Thats what i had to replace on the other amp to get the power light to come on.

And yes it reads shorted in both directions

Perry Babin · 2011-01-03 11:51 am

edit

Yes, you can replace it with a mylar.

mike49504 · 2011-01-03 12:01 pm

0.1 uf 50 volt?

Perry Babin · 2011-01-03 12:16 pm

Yes.

It probably caused L12 to open.

mike49504 · 2011-01-03 5:49 pm

L12 1 side:-9.69 other side:8.78

L11 1 side:27.42 other side:8.86

D26 1 side:8.84 other side :27.14 directly across it:18.50

D29 1 side:8.70 other side-9.54 directly across 18.35

Power light still doesnt come on so i have to track it down still

Perry Babin · 2011-01-03 8:39 pm

Both inductors appear open, what is the resistance directly across each one (amp off).

mike49504 · 2011-01-03 9:04 pm

L11:171.6K

L12:OL in both directions it flashes a number for a sec then goes to OL

Perry Babin · 2011-01-03 10:54 pm

L12 is definitely defective. The other one is likely defective also. I think they should have no more than a few ohms resistance.

Compare them to L10 and L13.

mike49504 · 2011-01-04 6:52 pm

Replaced L11 and L12 amps power light is back on. I still have pulsing voltages from every pin in the middle row of the driver board

Perry Babin · 2011-01-04 6:56 pm

Did you check each regulator individually? Are all of them producing the correct regulated voltage?

mike49504 · 2011-01-04 7:18 pm

7915
Leg2:-13.89 and is pulsing

Leg3: 13.22 and pulsing down to the 12's

7815

Lge1:12.67 and pulsing all over

Leg3:13.68 and pulsing all over

7905

Leg2 -13.88 and pulsing

Leg3: -490 and pulsing

7805

leg1:12.66 and pulsing

Leg3:5.03

Perry Babin · 2011-01-04 7:31 pm

7905: -4.90?

7915: +13.22?

mike49504 · 2011-01-04 7:48 pm

With the output driver board removed i have the following voltages

7915

Leg2:-17.98

Leg3:-15.17

7815

Leg1:16.69

Leg3:17.26

7905

Leg2:-15.16

Leg3:-4.91

7805

Leg1:16.39

Leg3:5.02

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