penta 150 amp 6603 no output

8 replies
C(
chrismiller (archived2)
Bronze
17 posts
Posted July 23, 2019 at 22:22 GMT
#2125726

Picked up a pair of Penta 150 amps, no longer connected to the speakers.

One powers up and outputs fine, the other has no output.  Senses input and green lights.

I'm thinking of using the amps to power some S75 speakers I have (I have two pair).  If I can't get the second amp to work, I may use the working one to power a Boston Acoustics sub that has a bad integrated amp.

Haven't opened them up yet.  The bad one has a bad scrape across the switch panel and the panel no longer retracts, so it's seen some abuse.  It also has different wires that the first one for the speaker output; they are both white and heavier gauge than the first working amp, where they were red and black wires.

Stickers on the base are different as well. 

The broken one reads

L  Type 6603

Serial Number    

04392960    3595   01

--

The functional one reads

L  Type 6603

Serial Number 

04067898   6547  01

Any thoughts?  

Thanks, Chris

DI
Dillen
BronzeModeratorFounder
12777 posts
Posted July 23, 2019 at 22:43 GMT
#2125727

Fuses?

Martin

C(
chrismiller (archived2)
Bronze
17 posts
Posted July 23, 2019 at 23:19 GMT
#2125728

The two T5A 250V fuses under the bottom cover seem fine.  Are there others?

DI
Dillen
BronzeModeratorFounder
12777 posts
Posted July 23, 2019 at 23:55 GMT
#2125729

No.

Does the relay click when going to green?

Martin

C(
chrismiller (archived2)
Bronze
17 posts
Posted July 24, 2019 at 00:06 GMT
#2125730

Yes, relay clicks when light turns green.  I am using the amplified speaker connections and I can hear faint music when light is red or green.  I will have to get a multimeter to confirm the fuses are OK.

C(
chrismiller (archived2)
Bronze
17 posts
Posted July 24, 2019 at 00:13 GMT
#2125731

One last post tonight.  When unit plugged in and set to "off" light is red.  Mode to auto, turns green, even with no signal.

C(
chrismiller (archived2)
Bronze
17 posts
Posted July 24, 2019 at 13:13 GMT
#2125732

Both fuses have continuity, so the issue is probably internal.  I see posts about cracked solder joints; will try to assess tonight.

SO
solderon29
Gold
1051 posts
Posted July 25, 2019 at 15:03 GMT
#2125733

The type 6603/1723 for North America (110v)has a heat sensor fuseable link in the input to the main power transformer,this may have failed?

There is a separate transformer for the standby supply

You should have 5A (F1)and 150 mA fuses(F2)in the base of the unit.The 150mA is for the standby supply which appear's to be functioning,as the light's change colour as they should.

In auto mode,the amplifier should respond  automatically when it receives audio at any of the input's.The sensitivity of the function depends upon the setting of the  "level" switch inside the drop down front panel.

The power relay may have burnt/oxidised contacts preventing the main amplifier from working?

If when you explore inside,the main amplifier supplies +68/-68 are in fact appearing ok,it will suggest that the signal is getting lost in the pre-amp  circuitry,possibly due to a faulty capacitor or op amp,but the pcb may have suffered damage too if the unit has been dropped etc?

Keep us posted as you venture inside.

Nick

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