General Forum

Re: Penta II repair

Frank Rizzo — Fri, 18 Apr 2008 13:23:57 GMT

Hi Keith and others...

With your help...both Penta II's are working...but only with the powerlink converted to speakerlink and in auto... they go into standby and active as they should.. They will not work with straight Powerlink..

THe screens are not working in any way...

Ideas...

Re: Penta II repair

Frank Rizzo — Fri, 18 Apr 2008 09:19:10 GMT

THanks Keith....will do this AM....!!

Re: Penta II repair

Keith Saunders — Fri, 18 Apr 2008 02:25:04 GMT

I doubt that the fault is on the input selector part of PCB2 where you appear to have been changing components. Whilst it has the circuit for the input select and line condition change circuit are on this module, your "Problem Statement" seems to suggest that for the few seconds it apparently works i.e. the green light is on and the sound lasts for a much shorter length of time, so the amplifier is more likely to be drawing more current than it should.

I suggest that in its failing state you check the + & - 68 volt supply. You can check the +68 volts by measuring across C46 on PCB1 and the -68 volts check across C49 on PCB1

If those are fine, then check the -15 volts at pin 4 of IC1 on PCB2, we know that +15 volts is fine because the Red/Green Led is working. The input selector area only uses +15 volts.

Re: Penta II repair

Frank Rizzo — Thu, 17 Apr 2008 17:41:33 GMT

In the auto position the light goes green for 5-6 seconds....and when you are sliding between auto and L position on the switch...you get sound normal level sound for just that 1/2 second....

In the auto position, if you turn up the volume alot...you can hear music...though very low and distorted....

Re: Penta II repair

magnushj — Thu, 17 Apr 2008 17:33:18 GMT

What happens when you provide a line level signal into line in?

Penta II repair

Frank Rizzo — Thu, 17 Apr 2008 17:26:12 GMT

All the capacitors and resistors look good on the PCB 2 board....we replaced all of the Transistors (except TR 3....couldn't find one)....

Same problem persists...turn it on...and light goes from red to green for 15-20 seconds...you get some sound for a 1/2 second when you switch from auto to left....

Could this be the NTC 330k ohm...resistor on the PCB 1?? That is clicking it off cause its bad and think its hot???

Ideas???