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2230 p750 power amplifier board toasted rebuild and upgrade?

Well, I got my parcel from IRM yesterday stuffed with loads of goodies.

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I cant wait to tackle the whole job. I have the LED kit to fit too.

Just out of interest, is there a overload relay system that I can retrofit to this receiver, I just wanted to eliminate the 'thump' on power up, or is it a simple case of turning the volume to minimum when turning on? I cannot say I have tried that.

And the other thing I want to highlight to everyone is that Baseballhack has posted me a replacement power amp board without taking any money from me yet. I gave him my address to get a costing and today he tells me that its in the post! I cannot believe the generosity of this man! I have insisted that I must pay him for his goodwill, but as yet I have heard nothing.

Is this the spirit of AK?

Also I sorta fell into buying these quite cheap (unfortunately the tuner knob was broken in the post due to poor packing). I just wanted the amp really to stand in for the marantz. My Dad has a modded delta 75 but from reading up the delta 30 is ok too. I haven't popped the covers on either yet, just given them a test run on some crappy speakers, I need to get some 2 pin din connectors to mock up my current leads.

Anyways, the leak setup will live in my workshop, where I currently seem to be residing! I want to get some ok ish bookshelf speakers to run with them too.

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Hi guys, well an update with progress! Baseballhack has kindly posted me a replacement power amplifier that I received this morning.

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I have now installed and it didn't got pop when turned on. I immediately adjusted the bias back to 5mv (across R774 & adjusted R765) and all seems well. I haven't put any amount of source through the amp yet as I think I have fallen against a problem. When I put my test meter across either left or right channel I have 30-35v dc across both channels. I have adjusted the power board (j808 & earth) and adjusted R810 to be 35.6v.

I have the volume set to zero, speakers on no input source, but aux selected (doesnt matter the source, still reads 30-35v).

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Is this right? I haven't left the receiver on at all because I don't believe this to be correct. :tears:
 
Well, I think so. I connected a pair of rubbishy speakers just in case, so now I have 0-10 mv readings. PHEW! Do you think I would be safe to try a source? :scratch2:
 
Sorry petehall, I forgot to say thanks for the prompt reply. How rude of me! I was caught up in the moment of panic about the output voltages. :worried:

Ok, Ill hook it up to something now. Wish me luck!
 
WHAHOO! my 2230 is alive!

I must say 'the traveling wilburys - not alone any more' never sounded quite so sweet!

I know its sad but I am feeling quite emotional about the whole thing. This reciever belonged to my late Granddad and I felt bad enough I broke it, let alone its now fixed.

:D:D:D:D:D:D:D:D:D

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Great end of story! Looks like a bulb is out in the middle of the dial there. It's a fuse-styled (but not a fuse!) 8V at 200mA bulb. The 300mA versions are easier to find but try to stick with 200mA rated ones.
 
Thanks for the tip rBuckner, I did think there was one out. I do have a full recap and an led conversion planned for this one, Ive got the parts just need the time to do it. I just want to enjoy it for a moment before I rip her apart again. :yes:
 
I feel like a gravedigger pulling this one back.

Well after a little dismantling and playing about and with a spare bit of time on my hands I managed to get the old board working. I basically removed every transistor resistor & cap and tested. The outcome is as below, albeit this is not showing the finished article because the op transistors that are shown are dead, but have been renewed.

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before
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I tried it this evening and all is well. I am pleased with the result. :thmbsp:
 
Hi everyone,

I found a 2230 in the trash along with a Thorens TD145 and brought them home. My wife was thrilled. I cleaned up the unit superficially and the right hand channel volume is very, very weak to nonexistent. I tested the preamp output and it works both channels. The main amp inputs gave only a signal on left hand side. Also, the amp/heat sink was cold for right hand amp and warm for the left hand side. I couldn’t see any obvious damage to parts on the board. I checked the row of fuses adjacent to the right hand amp and no blown fuses. I have limited experience with audio repair aside from building electric guitar pedal kits. What is the first thing I should check?
 
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