The case for avoiding molested boomboxes.

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Superduper

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I have a policy that when a boombox has been worked on before, I avoid them like the plague.

Consider this:
I have this boombox, a grail if you will.... I rebelted, dunked, cleaned, deoxit.... the works, to the boombox. However, for 3 years, I refused to reassemble it back into the shell because the music scan/search feature was not working. On another boombox, I would not care. On this one, there is good reason to want it working 100% perfect. So from time to time, I would do some more work to it. The frustrating part is that everything I tested appears to be in proper working order. Nevertheless, the AMSS light will not illuminate when that feature is turned on and none of the search feature was working.

Recently, fatdog gave me the heads up on a set of manuals that included the one I needed. Some negotiations and big $$'s later, we had a deal for just that one manual. Yesterday, my high $$ service manual came and today, I dug out the chassis and reviewed the connections. I suspected something wasn't exactly right because the way it was behaving suggested as much. Still it was that way when I got it and everything was connected in such a way that looked OK. Nothing seemed out of place. Nevertheless, without documentation, it was impossible to know whether it was all connected correctly. This is one of those boomboxes where wiring is tethered all over the place, like a rats nest.

So a quick review of the connections and comparing to the wiring diagram in the manual found the problem. The AMSS board had 4 connectors tethering it to various PCB's. 2 of the connectors was swapped. Both connectors were the same size/type and the lengths were approximately equal so it was easy to do but they went to different PCB's. It was that way when I got it so presumably, it was worked on before and the connectors swapped because I can't believe it came from the factory that way. The big $$ manual, it seems, was totally worth it.


So, in support of my argument to PASS on any boombox where any suggestion exists that it had been tinkered with before, my misconnected/molested boombox represents a perfect example why. Enormous amounts of time/expense can be wasted when something is connected wrong but no documentation exists to support or contradict it either way. When a boombox is received and not working right, the default presumption must be made that it is properly assembled as received and therefore used as a guide for proper reassembly after service. If just a wire or two was misconnected, then some educated guessing is often enough to correct the issues. However, when more repairs/modifications are performed, then it's almost best just to send the dam- thing back since almost surely, it will be a diagnostic black hole. To be sure, every component can be tested and found to be in perfect working order, yet if not connected properly, it will be impossible for it to be working 100% right unless the misconnected wiring is corrected.

From experience, I have corrected many such misconnections. They are more common than you think. Sometimes, intuitive guidance can be relied on and on certain circuits such as cassette motor drive connections, some reverse engineering is all that is necessary to figure out if it's tethered correctly. However, some connections simply is not easy to figure out. This boombox was my most frustrating one for 2 reasons. (1) it belongs to me so it's not as simple as just sending it back unfixed and (2) it's a grail so I was determined to get it fixed.

Anyhow, here is a suggestion for any of you guys working on boomboxes that you aren't familiar with -- do everyone in the hobby a favor and take many pictures, redundant ones if necessary to ensure you reassemble everything back the way it was. Someday, you may want to sell, trade, or commission someone to repair it for you. If it was not reassembled correctly, the issues mentioned above will definitely come into play and cause grief. The only question is how much grief and whether it is your grief or someone else's. If there is a suspicion that anything is not properly reassembled, then at least mention that to the repair person or new owner. At least they can approach the boombox differently when trying to correct issues.
 

redbenjoe

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May 6, 2009
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one other idea --
if the box is a very rare // must have // may never see it again grail or personal grail :-)

and you KNOW ?? --its been messed with -and that it may NEVER work right --

as long as the line-in operates -and the cosmetics are very pleasing ..
then --dont avoid it - but
just dont expect more than you bought
 

Superduper

Member (SA)
Makes sense Ira. In this case, we are talking about the AMSS circuitry. However, I speak about mystery work in general.

I would not necessarily strike a boombox if it has obviously been worked on if it's cheap enough. More likely however, is that the boombox will sell for more than I'd value or risk on an mystery situation. Been there and done that enough times to know that it's something I'd soon regret if I go that route.

Remember... some boomboxes simply don't have service manuals.
 

sony_apm_fan

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Apr 8, 2010
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Great advice Norm, but I would still take on a grail if I had any chance.

What I mean is that I'd rather have an M90 (for example) in any form as a starting point, previous tinkering ok.

But, I have been sent boxes that have been reassembled badly, mising bits and parts damaged. I hate that.
 

baddboybill

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Jul 14, 2009
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I do agree 100% with this Norm as when I 1 st started collecting and doing repairs on my own, I purchased a non working helix and took many pictures so I would be able to solder wires back in place and well I screwed up even with pictures from rushing to get it done out of excitement for getting it working. :thumbsdown: I got real lucky because only 2 wires were moved over from the original joints and I had figured it out because I had taken the pictures... Plus I had also received my sanyo mx920 with wires in wrong position on switch :sadno: So yes I agree 100% plus I am adding take time to make sure they are soldered or plugged into joints that it shows on your pics :thumbsup:
 

blu_fuz

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Jun 3, 2009
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I also agree with all of it. Pictures answer all questions, so take lots of them!
 

MasterBlaster84

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baddboybill said:
took many pictures so I would be able to solder wires back in place and well I screwed up even with pictures from rushing to get it done out of excitement for getting it working.
Oh man I trashed the power supply in an older surround sound processor (worth about $100) about 2 years ago because I lost focus on what I was doing. It had a bad bridge rectifier so I found a compatible replacement, the replacement had the label on the opposite side from the original. I made very sure I was aware of the swapped label so I would get the polarity right, well once I started the work I lost sight of this little IMPORTANT information and installed the BR with the label pointing the same direction as the original, of course I was now rushing to get it turned on so I didn't verify my work. You can see where this is going, I powered up and the CAPs on the power supply almost got red hot and now the Power Supply was more damaged then when I started. :thumbsdown:
 

Fatdog

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Norm, since I know which grail you are talking about, let me be the first to say - WE NEED PICTURES!!! :agree: :superduper: :-D :yes: :yes: :yes:
 

MasterBlaster84

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Superduper said:
You are lucky the caps didn't explode in your face. Seriously, it frequently takes no more than 5 or 10 seconds of reverse polarity in the PS to cause them to go kaboom.

In any event, those caps are damaged and needs replacement.
Norm I realized what I did as soon as the caps got hot, you could have heard a pin drop when I very calmly uplugged it picked it up and placed it back in it's box for disposal without a second thought. I was so disgusted with my self and knew It simply wasn't worth repairing at that point. :thumbsdown:
 

Superduper

Member (SA)
Well, it sounds like you already tossed it so it makes no difference now. However, just for future reference, reversing the polarity in a power supply doesn't necessarily spell doom for the entire device. If the power switch was not thrown, the damage would've been limited to the power supply, which is one of the easiest repairs we can ever hope for. One of the things to keep in mind is that there is a cost to education and whether you pay a school or pay for self-learning (via experience), there is a cost. I believe after that experience, you are smarter and wiser, right?
 

MasterBlaster84

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Superduper said:
Well, it sounds like you already tossed it so it makes no difference now. However, just for future reference, reversing the polarity in a power supply doesn't necessarily spell doom for the entire device. If the power switch was not thrown, the damage would've been limited to the power supply, which is one of the easiest repairs we can ever hope for. One of the things to keep in mind is that there is a cost to education and whether you pay a school or pay for self-learning (via experience), there is a cost. I believe after that experience, you are smarter and wiser, right?
This was an Outlaw 950 Pre/Pro, I powered it on with the main switch on the front panel. These simply aren't worth putting more than a few $$$'s in for repair, they also have a poor volume dial design that goes bad frequently and this one was already going out.

The part that sucks is I spent the time to make sure I got everything right then like I had just turned my brain off proceeded to do it wrong anyway. :thumbsdown:
It was one of those moments that you realize you just did something really dumb and just turn and walk away. :lol:
 

Ghettoboom767

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May 6, 2009
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Hi Norm-good thread here!
My perfect example is the Sharp GF-9595H I bought for 50.00 from Henrytai- the voltage selector was removed and it had a bad power supply(distorted bad when turned up and light & cassette motor slowed down when turned up!)
I after a while with Prime on the phone got the wires hooked up to ouput at 15 volts(I had 11) but the transformer got real hot! It was working for a while! Brighter & louder!

But After being on the phone for a while with him & doing some testing I think I may have touched the tester to the wrong circuit or component and now it's dead! :sad:
It's the only box I have that's totally dead! :no:

I'd love to have someone help me with this! It's been a pain since I got it! I love the 9595!
I hear you norm!
Have a great week-Jeff. :hmmm: :-O :huh: :annoyed:
 

Lasonic TRC-920

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Interesting thread and I have always felt the same way, but with cars. I would always rather start out with a stocker and then cut it up my way.

But with radio's it's just not as easy as, "this piece goes there".

So, where are the pictures of this beauty that you have repaired? Is there a link or are you still putting her back together?
 
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