• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

2500 from beyond the realms of death

Dear God this resistor reads 10ohms until power is applied or the leads are wiggled and I don't have any on hand. I am crying inside...



Sent from my HTC6525LVW using Tapatalk
 
Arrrrgh! I replaced both of them on the one I did as they looked pretty poor. Let me know if you'd like the part numbers of the ones I used. One is for the soft start and the other is for the fan low speed setting. By the way, there is a quality ball bearing Pabst fan that Tom/catrafter suggested to me that is nice in there behind the "tunnel". A bit pricey but it's quieter than the original type.
 
rBuckner said:
Arrrrgh! I replaced both of them on the one I did as they looked pretty poor. Let me know if you'd like the part numbers of the ones I used. One is for the soft start and the other is for the fan low speed setting. By the way, there is a quality ball bearing Pabst fan that Tom/catrafter suggested to me that is nice in there behind the "tunnel". A bit pricey but it's quieter than the original type.
Click to expand...

Thanks, the funny thing is I saw the picture of the bad ones in your thread, but since mine measured in tolerance I decided not to grab them. And now thinking back, I replaced 90% of the parts and didnt get the one part solely responsible for power to the transformer! :headscrat

Anyway I already made the order for all the big wire wounds and decided to replace the rectifiers as well.

The fan was running when I powered it up. Is that normal operation?
 
Yes, the fan will come on in high speed and pop to low as soon as the slow start finishes. Scares the heck out of you the first time though, huh?! :sigh::D
 
Ok guys. New Vishay rectifiers and wirewounds are in. But I am not in the clear. I powered up the power supply and filters only, nothing is plugged into the power supply. I have 85v rails and a steady 32v on pins 3 & 4 on J805, as per the service manual. I have lights and a fan on high. I plugged in the right side amplifier and powered up. Relays do not engage, dc offset and idle current are both zero and the pots have no affect. No smoke or blown fuses. just lights and fan. Progress?

I haven't started to track the problem yet, but I'm open to ideas:D

Until tomorrow....
 
At the risk of being the grasshopper assisting the sensei (being how I couldn't have gotten the pile you started with to this stage). It seems from my uneducated perspective that even though you powered the amp board, power still isn't getting to the amp board. I'm assuming, you're reasonably confident the PS output is good. Are the any test points you have reasonable access to on the amp board to prove nothing failed (harness wire, broken trace?) We all know you're close here. (Its sometimes easy to overlook the obvious) . I'm sure you'll have it sorted out soon.
 
ok, well I won't have any time tonight but I did find some problems. I compared the voltage powering the power supply, soft start, and both relays to the schematic and they were good. Not all junctions are listed. I double checked the thermal switches and made sure they were connected correctly, they were good. I randomly check voltage from chassis ground and find AC on the power supply. J805 which has 13vdc and 31vdc on 2 pins each also has 100vac on those 4 pins. I pull the power switch and partially disassembled and check it. The two wires from the switch to the soft start board are reading funny when i move the switch. So i deox the hell out of it and power up with the switch out. No more AC at those pins, only the correct DC. still no relay click.
 
Here are the transformer voltages for inquiring minds. They check out on mine.




Sent from my HTC6525LVW using Tapatalk
 
We are back in business boys! A hairline fracture in the soft start board had me going crazy! Both relays click, fan is nice and quiet. In fact it didn't start out on high speed.

The power switch won't disengage until the unit is unplugged, so I will take that apart and see if it's salvageable. The amps are not plugged in yet so hopefully no problems there. And the FM led is illuminated with no change from the selector switch and no others illuminating. The saga continues...



Sent from my HTC6525LVW using Tapatalk
 
I am understanding now why the last guy went nuts! But this receiver has met its match dammit!

So I'll start with the good. Both amps are running and stable. I have sound through both tape inputs. All tone controls work. The weird AC issue has been resolved. I have some new led's in, and I made a new ground lug for the phono.







Now the bad. Well, the auxiliary input produced intermittent, badly distorted
sound which I traced back to the RCA inputs. The physical plug will read short or open when moved around. There were some solid strand wires broken further up the insulation. I'm thinking about running new signal wire from the plugs to the rca's. This wire has been moved around to much and I cant trust it. Also I was getting auxiliary sound from every input in the selector switch. Then I recalled a thread where the shaft on the selector switch actually detached. So I grabbed the shaft and it came right out!




Also the power switch is shot. any leads on that would be greatly appreciated!

So all the important stuff is working. The phono board connections are the last thing to square away. Then maybe I can get some pictures of this thing in one piece uploaded!
 
:thmbsp:Way to stay the course!
Truly a labor of love! I couldn't imagine walking to a shop with the pile you started with and asking them to repair it ( not that I know of any place local that would have a clue on how to go about it)
 
nj pheonix said:
:thmbsp:Way to stay the course!
Truly a labor of love! I couldn't imagine walking to a shop with the pile you started with and asking them to repair it ( not that I know of any place local that would have a clue on how to go about it)
Click to expand...


Thanks. And if you still want to hear it before it goes, bring your 104's :D


well I fixed the shaft and rewired the auxiliary inputs and walla! crystal clear sound! AM and FM working. No lights on the input indicator though, but I have a stereo light.
 
Salbreth1 said:
Thanks. And if you still want to hear it before it goes, bring your 104's :D


well I fixed the shaft and rewired the auxiliary inputs and walla! crystal clear sound! AM and FM working. No lights on the input indicator though, but I have a stereo light.
Click to expand...

One I restored had a blown diode on the little circuit board the holds indicators, keeping them off.

Tom
 
catrafter said:
One I restored had a blown diode on the little circuit board the holds indicators, keeping them off.

Tom
Click to expand...


Thanks Tom. Thats the first thing I checked and it was good. I replaced it anyway including the cap. I won't have time to check it out today, but i'm sure ill find it. I received the scope bracket by the way, but its the last part going in. Thanks again.
 
You must log in or register to reply here.
Back
Top Bottom