McIntosh MR77 tuner - IC needed for MPX board - Page 3

mjatabor · 21st January 2012, 08:07 PM

I soldered the wire to the missing pins, put the chip in the socket, and it works fine, therefore I don't really need a new IC.

In the near future I will remove the IC socket, as recommended, and solder the IC chip direct to the PC board. There is plenty of working room. What is the advantage of doing a direct solder vs. using the IC socket?

Juergen Knoop · 21st January 2012, 08:11 PM

no, leave it as it is!

AuroraB · 21st January 2012, 08:21 PM

Leave it !!

I just looked at the schematic for the MR77, and it is certainly not MC 1309 or 1310. Your early tipper may be right about it being an MC or LM1303, as the pin configs seem to match.....
The schematic lists it with Mc part numbers only, so I'm not totally sure.

tauro0221 · 21st January 2012, 09:03 PM

Hi,
The reason to install an IC in socket is the easy replacement. If you solder it to the board you must have some knowledge on how to remove it or you may destroyed the board. In the way I fix a problem like yours is used an old IC cut the pin flush to the body and slide in under the piece of the leg left and solder it.

Mooly · 22nd January 2012, 06:53 AM

Quote:

Originally Posted by mjatabor

I soldered the wire to the missing pins, put the chip in the socket, and it works fine, therefore I don't really need a new IC.

In the near future I will remove the IC socket, as recommended, and solder the IC chip direct to the PC board. There is plenty of working room. What is the advantage of doing a direct solder vs. using the IC socket?

Pleased it's working.

Sockets can be a source of trouble, and with a different profile of wire than intended (the broken pins)... well lets just say it's not ideal although it may never give a problem in practice.

If you want to experiment with braid removing parts then practice on some scrap item, an old remote or something.

rayfutrell · 24th January 2012, 08:47 PM

Good job.

The LM1303 used to be made by everybody, but now it's so old even NTE has discontinued it. The LM1303 is a clone of the UA739 and here is a thread on finding a replacement.
Ray

ua739 Op Amp Replacement

mjatabor · 06:37 AM

I forgot to thank everyone for your help. It was a simple un-invasive fix. Tuner sounds wonderfully clear after a good cleaning of all the contacts.
All the best!

21st January 2012, 08:21 PM	#23
AuroraB diyAudio Member Join Date: May 2001 Location: Norway, -north of the moral circle..	Leave it !! I just looked at the schematic for the MR77, and it is certainly not MC 1309 or 1310. Your early tipper may be right about it being an MC or LM1303, as the pin configs seem to match..... The schematic lists it with Mc part numbers only, so I'm not totally sure. __________________ While the Lie leapt from Bagdad to Constantinopel, the Truth was still looking for it's sandals!

10th February 2012, 06:26 AM	#27
mjatabor diyAudio Member Join Date: Aug 2005	I forgot to thank everyone for your help. It was a simple un-invasive fix. Tuner sounds wonderfully clear after a good cleaning of all the contacts. All the best! Last edited by mjatabor; 10th February 2012 at 06:37 AM.

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21st January 2012, 08:07 PM	#21
mjatabor diyAudio Member Join Date: Aug 2005	I soldered the wire to the missing pins, put the chip in the socket, and it works fine, therefore I don't really need a new IC. In the near future I will remove the IC socket, as recommended, and solder the IC chip direct to the PC board. There is plenty of working room. What is the advantage of doing a direct solder vs. using the IC socket?

21st January 2012, 08:11 PM	#22
Juergen Knoop diyAudio Member Join Date: Jan 2007 Blog Entries: 3	no, leave it as it is!

21st January 2012, 09:03 PM	#24
tauro0221 diyAudio Member Join Date: Nov 2008 Location: Victoria,TX	Hi, The reason to install an IC in socket is the easy replacement. If you solder it to the board you must have some knowledge on how to remove it or you may destroyed the board. In the way I fix a problem like yours is used an old IC cut the pin flush to the body and slide in under the piece of the leg left and solder it.

24th January 2012, 08:47 PM	#26
rayfutrell diyAudio Member Join Date: Sep 2004 Location: virginia	Good job. The LM1303 used to be made by everybody, but now it's so old even NTE has discontinued it. The LM1303 is a clone of the UA739 and here is a thread on finding a replacement. Ray ua739 Op Amp Replacement

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