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It ain't easy.... being GZ!


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#61 THAFUZZ

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Posted 29 February 2016 - 08:47 PM

 



#62 THAFUZZ

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Posted 29 February 2016 - 08:51 PM

Not as excited as me! Eric the boombox whisperer!

Yeah! I like that. 'Eric, the Boombox Whisperer'.

#63 caution

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Posted 02 March 2016 - 10:31 AM

I'm whispering but it's not listening!
I think the balance pot is hosed. If it's in the center position or anywhere on the left side and I leave it there for a while, it will eventually start to pop and make noises. It also makes a whooshing noise as you turn it back and forth on most of the left side.

I took it apart again and applied Deoxit FaderGrease and bent the contacts up a bit, and it's still doing it. After I cleaned it I inspected it under high magnification and light, and the carbon tracks actually looked pretty good, so it must be something you can't see.

Joe, want to send me the other board? :-)

#64 blu_fuz

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Posted 02 March 2016 - 10:56 AM

Sure can bud, I'll PM you.



#65 caution

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Posted 04 March 2016 - 10:51 AM

Was this an early attempt at reviving her? :-)

 

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#66 blu_fuz

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Posted 04 March 2016 - 10:54 AM

No, that is Gregs 777 that was cracked.

#67 caution

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Posted 05 March 2016 - 12:56 AM

Time for some more pics, whaddaya say?

Cap work on the amp board, balance and volume pot work, before/after on the stereo mode switch, and some experimenting on a leaner version of the dial light LED conversion. I hope you like white!

 

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#68 blu_fuz

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Posted 05 March 2016 - 08:03 AM

Love the pics

#69 BoomboxLover48

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Posted 05 March 2016 - 08:07 AM

Wow! The Great Boombox Whisperer in action! :jawdrop:  :jawdrop:

I want to move to Oregon.  :yes:  :-D

Actually I love that place. 

 

GZ is one lucky guy to get all this help! :yes:  :-D



#70 -GZ-

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Posted 05 March 2016 - 09:16 AM

I'm speechless. You're my hero.

#71 Northerner

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Posted 05 March 2016 - 09:24 AM

Wow some serious work going on there...awesome :-)

#72 THAFUZZ

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Posted 06 March 2016 - 02:34 AM

Wow some serious work going on there...awesome :-)

I agree. Awesome!

#73 MyOhMy

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Posted 06 March 2016 - 09:55 AM

Dear me, you must have an ology or two and seemingly limitless skills for this eye-watering depth & scope of work. :yes:

 

Yep, I'm awestruck again! :w00t:  :yes:  :thumbsup:



#74 SLO

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Posted 06 March 2016 - 07:18 PM

Man I wish I had the know how to do more in-depth repairs and mods, Im in awe  :jawdrop:



#75 BoomboxLover48

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Posted 06 March 2016 - 08:05 PM

Dear me, you must have an ology or two and seemingly limitless skills for this eye-watering depth & scope of work. :yes:

 

Yep, I'm awestruck again! :w00t:  :yes:  :thumbsup:

Awestuck is another new word after Electrickery!  :w00t:  :lol:  :lol:



#76 ralrein1

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Posted 06 March 2016 - 09:04 PM

Yeah what MyOhMy and SLO said!Very cool to see all the intricate work I wish I knew how to do.My hat goes off to you sir.👍👍

#77 Superduper

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Posted 06 March 2016 - 09:04 PM

So that's what this thread is about, lol.  I thought this was GZ's feedback page and with my brief visits here and already knowing that greg is a good guy, didn't click on it until I noticed that this thread was growing (and with GZ himself posting) that made me curious.  Great job Eric.



#78 caution

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Posted 11 March 2016 - 04:03 PM

Wow thanks for the kind words guys (and gals :-D )
On a positive note, the balance pots are both fine, although they both "woosh" on the right side, which is why I was so keyed in on them. Turns out the scratching was coming from the aux mode switch! Both boards will be cleaned.

GZ if you want I can try and fix your dial window, I've got one too that has cracks and I've been thinking it might be possible to seal them if I could find a way to limit where the solvent goes. I'm thinking a piece of tape behind the crack, and completely tape the top with a slit barely wider than the crack so you can run a needle bottle of the stuff at high pressure along the crack.

Sounds a bit dicey so I haven't tried it yet, doesn't seem anyone here's tried it.... :hmmm:

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#79 Superduper

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Posted 11 March 2016 - 08:08 PM

GZ if you want I can try and fix your dial window, I've got one too that has cracks and I've been thinking it might be possible to seal them if I could find a way to limit where the solvent goes. I'm thinking a piece of tape behind the crack, and completely tape the top with a slit barely wider than the crack so you can run a needle bottle of the stuff at high pressure along the crack.

Sounds a bit dicey so I haven't tried it yet, doesn't seem anyone here's tried it.... :hmmm:

 

Forget about the tape.  Once that thin waterlike solvent is introduced, it will wick all the way through and into the tape, which will then become a permanet part of the window.  Even if you could get the solvent in there without it migrating to areas you don't want, the crack is old and probably already stained within the crack.  Since you likely can't wash off the stain, even if the solvent could manage to glue back the crack, the stain probably will still be visible.  Might be better off going to tap plastics and seeing if they can make something up that might work.  But first things first, tap plastics sell needle hypodermics for dispensing acrylic solvent, but even with that needle, there is no way  to get it ONLY into the crack without any on the flat part of the window.  It takes a ton of skill just to get it only along the seam of two parts to be glued without the solvent spurting off like an out of control, over-watered puppy. 



#80 caution

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Posted 11 March 2016 - 08:49 PM

Yeah, I bought a couple pieces of clear acrylic at Goodwill today and it doesn't get under the tape at all but you're right about the not working part, it won't get into the crack one bit. Even creating an opening on both sides didn't work.

 

TAP turned me away because it was injection molded, I was sort of surprised they didn't even want to try to make me something. It's not that complex of a part, maybe I'll spec it and have them make pieces I can weld together.



#81 Superduper

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Posted 11 March 2016 - 09:14 PM

A flat part won't work? If not how about get a thicker piece and router a relief along the edge?



#82 blu_fuz

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Posted 11 March 2016 - 09:20 PM

I would get a thicker piece and route the edge.

#83 caution

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Posted 11 March 2016 - 09:55 PM

Yeah, I may have them do that much for me, better than nothing!



#84 Superduper

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Posted 11 March 2016 - 10:16 PM

Well, let's be honest, you won't find brand new parts and this is unfortunately part of life working on obsolete items, even if this wasn't (in the grand scheme of things) a tiny virtually irrelevant brand in the electronics industry compared to giants such as JVC, Matsushiata, Sanyo/Fisher, etc.

 

So while an edge routered acrylic window might not seem as good as an original acrylic injection molded part, it should truly be a joy to have a brand new unscratched, perfectly clear new window as opposed to the discolored, scratched, cracked one.  You can't see the backside so only the front appearance would be important anyhow.  The only wildcard is whether they can flame polish or otherwise polish the routered edge so it's not white colored, and that might be important depending upon whether the mounted window sits proud of the cabinet face, or recessed.



#85 -GZ-

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Posted 12 March 2016 - 08:07 AM

Whatever you want to do is OK with me, Eric. I trust your judgement completely.

#86 caution

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Posted 16 March 2016 - 02:12 AM

Well Norm you got me back into TAP last Saturday and told them just to cut me a piece with 45's along the top and bottom. Then I had them cut me up a square rod that I'm thinking I'll glue together. Slips in nicely. Thinking I'll use some E6000 to bond them together, but first I'm going to look at the possibility of cutting out the cracked window and gluing the new face to the old molding so I still have all that there. I'm afraid it might look too open in there without it. You can sort of see from the angles on the original piece how they actually look quite close to what they made.

 

I finished overhauling the aux mode switches on both control boards as well as the stereo mode switch on the the original amp board Joe sent me (the dead one). The control board that was in the box is now completely scratch free.

 

That takes care of GZ's boards, but I wanted to repair the original boards first, they arrived last week. The control board only needed an aux switch cleaning so far, but there is a tiny bit of scratching coming through and it seems to be either on the bass knob or mode switch, they're the only real possibilities.

 

The amp board, I'm glad to say, is back from the dead! When I first powered it up I instantly got a hum on the right channel and nothing on the left, or maybe a little buzzing. Whatever. It was toast. So, I popped new 1392's in there and all of a sudden things were dead silent, save a little crackling now and then.

 

I was worried the big cap might be leaking like the other one, so I yanked it, but it was fine. I ended up finding an equal capacitance/voltage in a smaller size on a newer board from something else, so I put that on to be safe.

 

I started poking around with a ohmmeter between the good amp board and the bad one to see if I could find any differences, and I decided to start at the big transistor over by itself. Call it luck but the very first measurement I took was a hit! The diode in front of it was toast, totally shorted out.

 

It has the mark "Z 11" on both the good and bad boards. It seemed that meant it was an 11V zener, so I looked around on some scrap boards but nothing close to that. I ordered a variety pack with that value yesterday. At this point I wasn't sure if more was toasted on the board as well, so I bought some extras for the other two big transistors just in case.

 

I decided to go over to the surplus store near me today (hey, any excuse to go over there, ha!) and found some 10V and 12V zeners in their bins. I bought a couple of 12V zeners and to my delight the thing started working! I notice the drop across the diode is 12.2V, but the good board with the original diode still there is about 11.7V, so it's probably not off enough to be damaging, but I'll wait until I get the 11V zeners and pop one of those in there instead.

 

One thing weird was that with the shorted diode in there, not even the volume knob had an effect. My guess is this diode is part of the circuit that the audio is sent through for the alarm function, which under normal operation will completely silence the audio output.

 

There was a black wire double-connecting one of the stereo mode switch pins to the wire post it ended up at, and I took that off. Some funky changes to the resistor on the FM LED board were made but it seems to work!

 

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#87 THAFUZZ

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Posted 16 March 2016 - 07:51 AM

Fantastic work Eric. :thumbsup:



#88 -GZ-

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Posted 16 March 2016 - 08:16 AM

I am not worthy of this.



#89 blu_fuz

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Posted 16 March 2016 - 08:58 AM

^ hell yeah you aren't, send me that beast! hahaha



#90 -GZ-

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Posted 16 March 2016 - 09:57 AM

^ hell yeah you aren't, send me that beast! hahaha

Well if i aint worthy then you sure as f#ck aren't either!!! :lol: