ghettoblaster vintage lasonic boombox trc-931

[cadillacman]

Well here we go. A blast from the past hehe. A good friend of mine paid a ton of money on ebay for this dang thing. It was taken to another repairman becuse of some issues and when he got it back, not only did it still have issues, now it has a bad fugly toggle switch on it lol..

so i get it, heres the issues:
- left channel quieter than the right.
- left channel pops and cuts out, comes back
- left channel sometimes cuts out, comes back popping like a machine gun
- tape a does not work, bad belt.
- power switch hacked in
- broken antenna.

I go ahwad and tear it apart. THeres cold solder all over this thing, worst at the audio amp ics. I then notice the heat sink on the left channel amp is is loose. So i tightened it. Now the heatsink gets BLAZING HOT almost immeadiately. I get to looking some more, the left external speaker jack is broken and has a intermittent short..

SO i think what happened is the ic was alteady struggling with basically no heat sink and cold solder, add the shorting speaker jack, its a wonder this thing works at all.

The ic is a toshiba ta7270p. I plan on just replacing both ics to make sure theyre fresh. I will reflow any other questionable solder, and remove that shorted out external speaker jack.

Ive found the ics and replacement whip antenna on ebay so im set there, which leaves this power switch. He hates it, and i dont blame him.

Does anybody know or anyone with lasonic boombox parts?
Anybody know where i can buy replacement tape deck drive belts here in the states?

Heres a pic of the beast.

[momaka]

Re: ghettoblaster vintage lasonic boombox trc-931

That is a sweet-looking boombox.
Just need to whack the idiot repairman who wired the ghetto switch with a big hammer on the head.
I don't know where you can get replacement parts, but I hope you get it fixed. It's pretty cool.

[cadillacman]

Re: ghettoblaster vintage lasonic boombox trc-931

already making great progress..

i figured id go ahead and reflow all the solder joints that were bad.(there were ALOT around the audio section and also a couple almost no solder at all joints on the control board.

I was happy to now feel the left side audio ic cool to the touch, but my left speaker still crackled.. Not so sure its an ic issue now, i poked around some more. Theres 3 terminals going to the external speaker jacks. Ones ground, ones audio in, ones audio back out of the jack. With speakers connected, the contacts inside open up, shutting off the internal speakers to power the external ones. Without external speakers hooked up, theres a contact thats supposed to connect the audio in to the audio out( so the speakers in the boombox work) There was a really poor connetion there due to rust/dirt/pop. I cleaned it out very well, SPEAKERS NOW WORK PERFECT.
Previously the adjustments all kind of crackled too, thats gone. Id assume some bad solder was the true reason for it.

so i guess that leaves me to find an antenna, possibly some belts for the tape a player if he wants that fixed, and figure out what to do with this horrible power switch.

[kaboom]

Re: ghettoblaster vintage lasonic boombox trc-931

Get some of these: (images)

No WD-40 on those pots and switches, even if it's "just temporary."

Belts can be found here:

www.studiosoundelectronics.com

Nice to see someone keeping an oldie going, rather than running out to Target and getting some fake POS.

Good luck- you've got a nice project.
-Paul

Edit- do the 1N400x diodes in the power supply look like they've been running hot? If so, change 'em to 1N540x's. Such as 1N5402's.

[cadillacman]

Re: ghettoblaster vintage lasonic boombox trc-931

youre damn right. this beats the hell out of korean krap made today. the caps in this are 30? years old, not bulged and still working fine.

thank you for the advise and link, this is gonna be a fun project..

[cadillacman]

Re: ghettoblaster vintage lasonic boombox trc-931

heres where were at so far..

I still want to get a little pbr can charm, drill out the center, install onto the toggle switch to make it a little more his style but its getting there. The audio is great now, so progress at least. Waiting to hear back to wether he wants to fix the other tape deck antenna and a couple other odds and ends.

http://www.youtube.com/watch?v=MCg476N0LCk

[Agent24]

Re: ghettoblaster vintage lasonic boombox trc-931

Just need to whack the idiot repairman who wired the ghetto switch with a big hammer on the head.

[lti]

Re: ghettoblaster vintage lasonic boombox trc-931

A ghetto switch makes a ghetto blaster even more ghetto.

I call modern boomboxes ghetto blasters, but the only one I have seen that is close to a real ghetto blaster is an Emerson from 1999. The internal construction could be described as "ghetto rigged." I might have to take it apart again. I already replaced a bad voltage regulator, but now it sounds like a filter cap is bad.

[kaboom]

Re: ghettoblaster vintage lasonic boombox trc-931

Those amp ICs can be used either dual-stereo or BTL. Since there's one for each channel, each one is BTL. Congrats- you're putting more power to each speaker in that thing than the cheapies pull from the wall!

I told ya you've got a nice project!

Are the caps in there Rubycons? Seen them in some older Magnavox and Sanyo boomboxes...

I've attached pix of the "things that look like boomboxes." Would you believe there are people who would have a nervous breakdown if you torched these things??? Those same people would "Garrett Smash" that nice LaSonic.

-Paul

Edit- I've solved the switch problem:
http://www.allelectronics.com/make-a...SSEMBLY/1.html
What could those be from?

[Th3_uN1Qu3]

Re: ghettoblaster vintage lasonic boombox trc-931

Ah, gotta love the round boombox attempts. Those barely hold a candle to the cheapest flavor of computer speakers. My family used to have a real boombox back when i was like 6 years old, but the radio broke and it was thrown away.

[weirdlookinguy]

Re: ghettoblaster vintage lasonic boombox trc-931

Any idea what your friend paid for that? My dad was a big ghettoblaster guy back in his day, I think it would be a real cool gift to find something like this for him.

[kc8adu]

Re: ghettoblaster vintage lasonic boombox trc-931

i still have a jvc with am/fm/sw.
rare.

[kaboom]

Re: ghettoblaster vintage lasonic boombox trc-931

bump


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