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Profile picture for user Link555

This one is now on the desk.

 
 

The unit is pretty good shape, others some minor signs of liquid "ingestion" on the top panel.

 
The unit looks stock, and I can see a few bubbled electrolytics in there.
 Alland all a nice build, with tiny input transformers on the 6 mic/line ins, and two output transformers on the XLR outs.
 

The owner says the EQ is sounds great when it works. The EQ is interesting because its a passive tone stack with tantalum caps.

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Profile picture for user BobAnalogue57

BobAnalogue57 Fri, 02/26/2021 - 21:30

Link555, post: 467949, member: 31690 wrote:
Just a recap and repair. Their have been 4 trace repairs. The age has not treated the pcbs well. Pads were lifted around the transistors, almost same area on all the boards. Only one was ok so far.

Hey Link, looking great, truly great . . . We'll give it a test drive once the spark plugs and points are tootled up right . . .;0) I have only tried it out twice as I mentioned . . the first time it was working seemingly as supposed to . . the next not.

It to me had a voice . . a unique sound . . I think the input trannies could be a good part of the reason . . .

I collect guitars . . including Japanese late 60's early 70's they are killer pieces to me.. . . and play killer too ;0)

And I'm a fan of Yamaha . . they are the universal bench mark group for the average musician, student level to Pro level . . in so many categories . . including enthusiast in my view.

This unit caught my eye initially by its roomy layout and wonderful appearance in Black with two nice VU's. I'm in love with, and am addicted to, VU's ;0)

Even in low end rack equipment . . Yamaha runs high in quality in any sub-category for me . . .

My first guitar was a Yamaha acoustic that my mom bought for me in 1964 after I watched the Beatles for the first time ever on Ed Sullivan . . . Mom paid $45 for it back then . . . and reminded me of that daily ;0) . . . and the deal we made that I would practice for an hour every day after school ;0)

I have a few of their 1 U GC 2020B's and love them for where I use them.

Great quality build on Yamaha even at the low end 70's home recording and FOH level as far as I am concerned.

The PM 180 has stereo headphone out, pan LR, XLR in and out the door . . and pads for line/mic levels . . a mini rack 6 channel mixer with in and output trannies . . For a solo gig acoustic show . . . perfect and hopefully for some coloration on drum tracks possibly . . . or even room ambience mics boiled down to LR . . . a subtle form of natural compression and paddy soft EQ as I recall . . . hopefully a nice tool for the toy box . Link you are the man thanks so much ;0)

You can buy these for under $200 anywhere right now . . . so why the trouble for such a low budge piece ??? ? gut instinct i guess . . I remember the listen and thought it sounded great . . so why not gamble on Link ? . . . he's the best !!

Profile picture for user Link555

Link555 Sun, 02/28/2021 - 09:21

The pm-180 is back together. Recapped and few a repairs. The main power supply dropping resistors were burnt open. I replaced the 1/2 watt Resistors with 3W. I changed the power cord, because even the unit was properly grounded inside, some cut the ground prong off the chord. Aside from the many lifted trace repairs, I also had to change channel 6 connector as it was intermittent.
    

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Profile picture for user Link555

Link555 Sun, 02/28/2021 - 10:06

Boswell, post: 467965, member: 29034 wrote:
Impressive! That binfull added up to a lot of caps to change.

Only a few were gone, but the request was to refresh all of the electrolytics. There were a lot of electrolytics in the signal path on this unit. What was nice was there were only four standard 10uf,47uf, 100u and 470u.

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Link555 Sun, 02/28/2021 - 10:17

Kurt Foster, post: 467963, member: 7836 wrote:
you sure performed a lot of surgery on it. i can't wait to hear from you what you think of how it sounds!

The only opinion that matters is the owners :). The input transformer seems decent. It seems to have slight bump around 4K and starts to rolls off around 80 hz. The unit has decently low noise floor and has a good amount of gain. I believe this is destined to be used as a sub mixer, but adding direct outs would be a useful option. If it was mind I would play with the eq frequencies a bit, the are the pretty powerful. They seems to be around 10khz and 100hz. Might be nicer to be 12khz and 80hz...
    

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