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New member, MX-130 issues


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Hi everybody, I am looking for some help/advice.

We have a Carver MX-130 that needs help (probably deferred maintenance). My wife had it for a long time before I entered the picture (hand-me-down from audiophile FIL), and over the years it's developed dropouts on mostly the left channel that sounds like dirty pots/connectors...I was always able to engage a few knobs/switches/buttons and after a few jiggles I can mostly get the channels back to acting normal. This eventually got worse of course.

A while back I popped it open assuming I could spray Deoxit here and there and get it acting normal. I've done this kind of thing before with music gear so I'm not in the dark. It was filthy inside and did my best to clean it up, but a few of the controls are kind of difficult to get to without serious disassembly, so I was not able to really do a good job of squirting all the switches/pots/buttons. It was a little better afterwards, yet the problem didn't fully go away and it seems to have come back.

Lately we've noticed the FM tuner (and AM tuner to some degree) acting flakey. Turning it on first thing from being cold, it will tune in a local station fine (LED meter lights all the way up), and after as little as a few minutes to a few hours, the signal drops out and it's just playing white noise. With or without an antenna it doesn't matter. Sometimes when I've switched inputs i.e. from phono etc. to the tuner, the digital radio station readout is totally garbled. I can turn on a cheap-o iCrap iPhone dock/clock radio in the same room and it has no problem picking up the same station all day long.

Is the radio tuner a module thing that can be swapped out easily, or is it something integral to a board in this thing, i.e. is it fried or maybe there's a bad cap or component somewhere in the circuit? My FIL has said he's never been lucky with the tuner on this, and he's offered to take a look....he has an ultimate set of tools and the skills to troubleshoot it, but I just want to figure out if it's worthwhile at this point.

I'm on the fence about selling it off and I would be fine just getting a 2nd hand, working quality receiver.  Maybe something to match the SL-QD33 turntable we mostly use with the Carver.

WWYD?

(Sorry this was a damn long post)

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Hello and welcome aboard.

 

It is most likely this IC:

 

https://www.ebay.com/itm/TC9147BP-IC-to-repair-CARVER-MXR-130-150-900-2000-THE-RECEIVER-TX-2-TX-11-TC9147/220863094475?epid=1531991873&hash=item336c775ecb:g:-owAAMXQya1Q8fsP

 

The same seller has lots of MXR-130 related restoration parts. I bought most of them to get my MXR-150 up and running.

 

I'm no expert so wait for the techs to chime in. 

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Welcome to the Carversite Cornfarmer. Nice receiver you have there. I have the MXR150 and from old age it was acting up once in awhile so I found Greg at Nelionaudio and he did his magic and life is good. ~^

 

Enjoy the site and absorb all the information that is available here. There is PLENTY!!!!

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Welcome Cornfarmer!  I've fixed several of these. The trouble spots for drop-outs: #1 by far is the output relays. You know it's them if you crank it up and it starts playing fine. Change them no matter what. Next is the TAPE MONITOR switch. You can DeoxIt from underneath. There is a ribbon cable that operates the switch, which is located on the Input Board, remove the bottom cover for easy access. Lastly, Volume and Balance potentiometers, if DeoxIt doesn't fix them, you might need to replace them, they do go bad. As for your tuner issue, there is a variable capacitor on the Tuner "sandwich" behind the display. Use a Sharpie to index it's current setting, give it a few twists with a small screwdriver and return it ti it's original position. Blow it out with one of those computer cleaning cans of air. That cap is available from Circuitsandconcepts, so are output relays. See how far those tips get you. 

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Hello cornfarmer, and welcome to thecarversite.com. We're glad you're hear. ;) There is a lot of information here, much technical know how, and as you've already discovered, a pretty good bunch of folks that are happy to help. 


Once you get to Novice status, please consider uploading some pics of your gear in the Members Systems area. We all like pics of all kinds of audio gear.


In the meantime, kick your shoes off, turn up the music, and welcome aboard.

 

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Welcome @cornfarmer, I think the steps @kve777outlined is the best course of action.

 

That receiver is worth repairing..., no one will appreciate it like you will, once repaired.  And, it's a nice unit that many of us here have in our offices or garage systems with a nice pair of speakers.

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  • 2 years later...

Hello, everyone,

  I just joined this forum. Thought I should finally do this, since I do occasionally work on Carver units, as well as Phase Linear. Nice to see this forum exists! So, my issue is the same as is discussed here, concerning FM issues on the MXR-130. Indeed, diddling with the TC251 trimmer cap, brings back the FM. Then it would go out again, so I would adjust that trimmer slightly, and leave it at that new setting. Again, after a while, the problem returns. So, I ordered the kit offered by Circuitsandconcepts, which consists of the trimmer cap as well as the IC251.  I figured may as well replace IC251 while I have that board removed. I see in the manual the alignment procedure does cover adjustment of TC251, so hopefully that will go smoothly.

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