No radio FM or AM

[Starfire]

So I bought a Toshiba Bombeat 18 (RT-S893) and have no radio at all, no FM or AM, just a pop when I switch between them or to the radio. I'm kinda guessing the AM/FM IF Chip (TA7614AP) since neither works and I have no tuning LED activity.

Here is the block diagram.

Any other ideas??

 

[BoomboxLover48]

Give the band switch and function switch a good cleaning with Deoxit. That is the first thing we should do.

 

[Starfire]

Already tried that, no luck...

 

[Starfire]

Well my original assumption was correct, replaced the TA7614AP and lo and behold I have radio! Was just lucky I could find the chip to replace.

 

[MyOhMy]

Well my original assumption was correct, replaced the TA7614AP and lo and behold I have radio! Was just lucky I could find the chip to replace.

You sound so confident and casual about this, how did you think of this? I'd have no clue whatsoever - I don't even know what a chip looks like never mind how or where to get a replacement!

 

[Starfire]

I've been fixing, building and modding electronics for over 20 years now so I've just become good at sleuthing out problems, it comes from experience now, but there is only one way to learn, that's to try it.

If you google the chip you can see the data sheet and what it looks like: https://www.google.com/search?q=TA7614AP&es_sm=93&tbm=isch&tbo=u&source=univ&sa=X&ved=0CB4QsARqFQoTCI3E6qPVxccCFQuGDQod0koMkg&biw=1920&bih=989

And a quick search on fleabay: http://www.ebay.com/sch/i.html?_odkw=https%3A%2F%2Fwww.google.com%2Fsearch%3Fq%3DTA7614AP%26es_sm%3D93%26tbm%3Disch%26tbo%3Du%26source%3Duniv%26sa%3DX%26ved%3D0CB4QsARqFQoTCI3E6qPVxccCFQuGDQod0koMkg%26biw%3D1920%26bih%3D989&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.XTA7614AP.TRS0&_nkw=TA7614AP&_sacat=0

It can be a very rewarding hobby both in satisfaction and money (fixing a $250 junked monitor with a $2 fuse) but there are times where it can be quite frustrating, but it's well worth learning IMHO.

 

[Starfire]

As to figuring out this problem if you look at the block diagram you can see the AM and FM reception pretty much follow separate paths to the amp (Which works since AUX in works) except for passing though the TA7614AP. Since I had no audio at all on either band (Not even Hiss) that lead me to believe that was problem. Also if the problem occurred after the 7614 I would have still had a tuning light as it controls the activity of the tuning LED.

It's kind of like being Sherlock Holmes following the clues led to the answer, sometimes it's not as easy, it could have been a passive component, or a bad solder joint, but again from experience I looked over the board and visually everything looked good and did some quick probing with a multi-meter which again led to the chip.

 

[caution]

Glad to see this kind of effort going on, nice job!

 

[Starfire]

I might not have if it was a pretty common box but I don't see many Bombeat 18s when I search online so figured it was worth fixing. Just need a belt for the cassette deck and it'll be back to %100 function.

 

[trippy1313]

Good work, you going to find a new chip and replace it? Sounds like you have a pretty good idea what you're doing.

 

[Starfire]

Already did, installed a socket so if future problems arise the chip can be changed easily but the box is tuning well now, kind of amazing how well it sounds on FM broadcast.

 

[trippy1313]

Cool. Great job. Did you take any pics of the process? If so post em! We all love some good info pics.

 

[MyOhMy]

I've been fixing, building and modding electronics for over 20 years now so I've just become good at sleuthing out problems, it comes from experience now, but there is only one way to learn, that's to try it.

If you google the chip you can see the data sheet and what it looks like: https://www.google.com/search?q=TA7614AP&es_sm=93&tbm=isch&tbo=u&source=univ&sa=X&ved=0CB4QsARqFQoTCI3E6qPVxccCFQuGDQod0koMkg&biw=1920&bih=989

And a quick search on fleabay: http://www.ebay.com/sch/i.html?_odkw=https%3A%2F%2Fwww.google.com%2Fsearch%3Fq%3DTA7614AP%26es_sm%3D93%26tbm%3Disch%26tbo%3Du%26source%3Duniv%26sa%3DX%26ved%3D0CB4QsARqFQoTCI3E6qPVxccCFQuGDQod0koMkg%26biw%3D1920%26bih%3D989&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.XTA7614AP.TRS0&_nkw=TA7614AP&_sacat=0

It can be a very rewarding hobby both in satisfaction and money (fixing a $250 junked monitor with a $2 fuse) but there are times where it can be quite frustrating, but it's well worth learning IMHO.

Right..................OK.....looking now.....................BINGO! Cor, I'm in awe!

As to figuring out this problem if you look at the block diagram you can see the AM and FM reception pretty much follow separate paths to the amp (Which works since AUX in works) except for passing though the TA7614AP. Since I had no audio at all on either band (Not even Hiss) that lead me to believe that was problem. Also if the problem occurred after the 7614 I would have still had a tuning light as it controls the activity of the tuning LED.

It's kind of like being Sherlock Holmes following the clues led to the answer, sometimes it's not as easy, it could have been a passive component, or a bad solder joint, but again from experience I looked over the board and visually everything looked good and did some quick probing with a multi-meter which again led to the chip.

Sadly, my brain doesn't work on things electrickery but I can follow the logic you explain so I'll thank you for taking the time to explain it as you so kindly have. I can solve a problem but it needs to stare at me first so I can see it.

 

[Starfire]

No problem, if you ever do want to get into electronics just start small buy a little kit from a company like Sparkfun they are pretty good with explaining things along the way.

 

[MyOhMy]

No problem, if you ever do want to get into electronics just start small buy a little kit from a company like Sparkfun they are pretty good with explaining things along the way.

One step at a time, that's me. Only this morning I looked on YouTube for an idiot's guide to soldering a connection and how to use shrinktube/heat tube - a thing I'd never heard of before I found this forum. There's certainly a lot to learn even at a basic level.