Wacky Issue Shared Between Two Blasters

[Gluecifer]

Thought I'd post about this, not sure if anyone can help, but hey, you gotta try!

I have an issue with two of my radios, namely the Taira M90 and my Sanyo BigBen, that when I'm walking with them, running on battery power and playing a tape, that the right channel makes a bit of a pop/crackle and drops out. A little tap on the right side brings it back, but it can happen a couple of times. I must say this happens at mostly innocuous times, it's not like they've been suddenly jarred or something. I walk carrying them by the handles, but it's not like I'm swinging them about.

I originally thought this was due to batteries crapping out, but they both do this even on brand new Ds.

Both radio's have less than perfect power sockets, as in they need a good waggle or exactly the right sized AC cord to power up, and the BigBen sometimes does this right channel drop on AC if the cord isn't in correctly.

What could it be?? I know inside that everything is connected securely and find it hard to believe something has worked it's way loose.

Is it possible to have the switch the changes between AC and DC needing attention or a clean? Or is this barking up the wrong tree?


When this just happened occassionally, and it is occassionally, on the Taira M90 I could dismiss it to it's own little eccentricity. But now it's happened on the BigBen I've figured it's worth looking into.


Thanks, rockers!



Rock On.

 

[tshorba]

I would check the circuit boards for any breaks or dry joints. The AC power should not effect left right amps, but if the circiut board has issues the pushing in of the power cable might cause (the break or dry joint) to dissapear for a short time. Just my guess..

 

[Superduper]

Is it possible to have the switch the changes between AC and DC needing attention or a clean? Or is this barking up the wrong tree?

The AC/DC switch is common to both L/R channels so it has absolutely nothing to do with your issue unless the boombox is quitting / starting completely -- if that switch is at fault, it will be all or nothing.

Based on your description, the only thing common to both boomboxes is the OPERATOR.

Ok, seriously, you stated that the issue occurs while playing a tape and while carrying the boxes. These two things plus the way the boomboxes are being carried are what they have in common. I suspect that the capstan freeplay is set loose and when carried, the capstan will shift in/out pulling the tape with it and causing it to go off center hence one side dropping out. I might be wrong, but I might be right.

 

[Fatdog]

I know on my M90 that the Line-In / Phono switch will get wonky from time to time and it ALWAYS causes problems with the right channel - NEVER the left channel. That's where I would start on the Taira.

 

[Superduper]

I know on my M90 that the Line-In / Phono switch will get wonky from time to time and it ALWAYS causes problems with the right channel - NEVER the left channel. That's where I would start on the Taira.

Rick said the dropout happens during the following conditions:
(1) when he is carrying it,
(2) operating on batteries
(3) and while playing a tape.

 

[tshorba]

Rick also noted

"Both radio's have less than perfect power sockets, as in they need a good waggle or exactly the right sized AC cord to power up, and the BigBen sometimes does this right channel drop on AC if the cord isn't in correctly."

this is what led me to think of dry joint or circuit board broken trace

 

[Gluecifer]

Very interesting replies! Thanks a lot! I'll investigate the sockets further, Tshorba, and get two AC cables I know work 100% and use them exclusively on them and see how that goes.

I think Bobby might have hit the nail on the head though!

When I carry them my leg will naturally brush against the back of the case occasionally, right when the phono/aux switches are!

That sounds to me like it could be be moved just enough to drop the channel!

I'll give em a squirt of DeOxit and then put some tape over them to see if that makes a difference. I'll give it a week of carrying and then see what happens.

If that doesn't work I'll try using the radio for a week on the walks to and from work and see if it happens, that would give Norm's theory a good experiment.


Love you guys. Different perspectives and ideas are what makes the world go around!



Rock On.

 

[Lasonic TRC-920]

 

[tshorba]

glue I have a box full of square type and half fig8 (flat one side) power cable for older boxes if you need some. Dont use normal fig 8 as they dont always reset the battey switch.

 

[Gluecifer]

Ohh awesome! They're the ones I'm always in short supply of!!

Might order a couple off you, Tshorba!



Rock On.

 

[stormsven]

Thats happened to me too . It was loose and dirty line in/phono switch. So i agree with Bobby here. Use to switch back the right channel after moving the switch 2-3 times. Thats was my firs guess too. Can be from bouncing around with boxes .

 

[45player]

Don't ignore the internal Record/Playback changeover switch- These get oxidized very easily and cause all kinds of audio dropouts and other problems, such as whistling feedback or pegged VU meters.

 

[beverlyjean2]

The Sanyo Big Ben aka MX=960K uses circuit boards some of which are double sided. The way they are mounted in the unit they could be subject to flexing when the unit is carried by the handle. I wonder if your other box uses the same type of boards. If you see foil traces on both sides of board you've got double sided boards. These traces are connected via small eyelets that will appear as little solder dots sometimes with paint on them. They almost look like a part would have belonged there. I have not seen cracks in these boards but I have had very good results repairing units with pesky intermittant problems by heating and adding solder to these small eyelet connections that make the electrical contact between the upper and lower board traces. Note: on early Toshiba products I would solder every single one of them before any trouble shooting was started.