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Inversing the preamp chip on RX-5350


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#1 mmcodomino

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Posted 14 April 2016 - 08:24 AM

Hi guys!

 

Brian and I are currently in the process of trying to fix a 5350 and it seems one channel of the preamp is deal. Can we just inverse the 3-pin IC to check if that is the solution?

Here is a data sheet of the chip:

http://www.weisd.com/store2/NTE373.pdf

 

Thanks a lot in advance!



#2 TW5

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Posted 14 April 2016 - 09:55 AM

Doesn't look like a good idea at the moment

also need more info

Where is that part from ?



#3 toshik

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Posted 14 April 2016 - 11:37 AM

What are the symptoms? I've fixed them before.

#4 mmcodomino

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Posted 15 April 2016 - 02:55 AM

What are the symptoms? I've fixed them before.

 

Everything is working except for the left VU meter and the left channel when it is playing a tape.
Radio is strong on both channels and in stereo, so is line in. Just the left VU meter does not move to the music.



#5 toshik

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Posted 15 April 2016 - 03:19 AM

This is very typical issue. Does not need two of you to fix :-)

#6 mmcodomino

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Posted 15 April 2016 - 04:39 AM

This is very typical issue. Does not need two of you to fix :-)

 

We already took the record bar apart and cleaned it. Same with the stereo/ambience switch.

Same symptoms. :(
What could be the cause of the problem?



#7 toshik

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Posted 15 April 2016 - 06:55 AM

Cleaning won't fix it

#8 BoomboxLover48

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Posted 15 April 2016 - 07:05 AM

It is very common for the corner of the board on the left side to crack and and kill the left VU meter function. I had that issue with one of my 5350.

 

The second picture shows the crack. I used signal tracer and found the problem.

 

 But no sound from the left channel and left VU meter not functioning could be related to signal loss due to another problem.

Attached Files



#9 BoomboxLover48

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Posted 15 April 2016 - 07:07 AM

Cleaning won't fix it

Then what is your suggestion?



#10 baddboybill

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Posted 15 April 2016 - 07:08 AM

I would say check tape head and wiring for issues with left channel on deck🤔. Or function switch


Bad Boy Bill

#11 jimmyjimmy19702010

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Posted 16 April 2016 - 03:35 PM

Then what is your suggestion?

he wants you to beg. :-)

#12 BoomboxLover48

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Posted 16 April 2016 - 05:30 PM

he wants you to beg. :-)

:-D :-D :lol: :lol:



#13 BoomboxLover48

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Posted 16 April 2016 - 06:14 PM

This is very typical issue. Does not need two of you to fix :-)

 

Cleaning won't fix it

 

 

We beg! Then how they can fix it?



#14 mmcodomino

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Posted 17 April 2016 - 03:01 AM

Thanks for your help so far. The board is not cracked anywhere. We just cleaned the function switch as well and are in the process of changing the belts right now which we might as well do while we are at it.
I'll let you know what it does once it is back together. :)



#15 toshik

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Posted 17 April 2016 - 03:29 AM

We beg! Then how they can fix it?

Your mailbox is full :-)



#16 mmcodomino

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Posted 17 April 2016 - 03:51 AM

No results. Same issues as before. :(

I got you message, toshik. Thanks! Where are you located? i don't feel like sending the board around would be a good idea though.



#17 toshik

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Posted 17 April 2016 - 04:25 AM

Location St. Augustine, FL



#18 bredgeo

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Posted 27 April 2016 - 10:45 PM

Hey all,

 

Thanks for the info and stuff!!!!

 

Toshik, I would love to sent the board... but you being in the US and the posties in Europe and America not always being nice, I don't wanna chance it!!!! :blush:

 

I think the chip we had a look at and changed might not be the preamp... I got the schematics, met up with a guy here that siad he will be able to look at her... I am gonna try that.

 

Later!



#19 zzmbie

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Posted 07 August 2016 - 07:20 AM

Hey to all,

 

i`m new here, but not in Boomboxes.

 

I have the same problem with the right channel, also only when tape is playing and only when the switch is on stereo. On ambience and mono both speakers working. :bang:



#20 toshik

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Posted 07 August 2016 - 10:21 AM

As I noted above it's a common problem

#21 T-STER

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Posted 05 January 2017 - 06:24 AM

 

As I noted above it's a common problem

 

You really are an irritating unhelpful member of this community.

Why don't you just tell people what fixes you have provided in the past so it can be archived and used for years to come?

So annoying, either help or stfu tbh.

 

 

I'm glad you said it Docs, I was just scrolling down to type the same.

 

Having what i assume is a grown man typing "i know it is" or similar to each post of a member searching for help is childish and unhelpful. If my 11 year old son acted like that i would be disappointed....



#22 BoomboxLover48

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Posted 05 January 2017 - 09:39 AM

One of the main functions of site is to help each other who is interested in this hobby.  :yes:

We all should contribute! :clap:

I always try my best with the little knowledge I have... :yes:



#23 Lasonic TRC-920

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Posted 05 January 2017 - 10:12 AM


Frustrations aside, please keep it clean. 
 
 

Hi guys!
 
Brian and I are currently in the process of trying to fix a 5350 and it seems one channel of the preamp is deal. Can we just inverse the 3-pin IC to check if that is the solution?

Here is a data sheet of the chip:
http://www.weisd.com/store2/NTE373.pdf
 
Thanks a lot in advance!

 
Max, has this problem been solved? Can this thread be closed?

#24 docs

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Posted 05 January 2017 - 10:51 AM

As a Brit, that was clean.

Sometimes some people just need telling but I am happy to see resolutions to problems like these from those that know, if indeed there is such a person :)



#25 T-STER

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Posted 05 January 2017 - 11:09 AM

One of the main functions of site is to help each other who is interested in this hobby.  :yes:

We all should contribute! :clap:

I always try my best with the little knowledge I have... :yes:

 

Amen to that man, nothing better than helpin another brother out with a fix :-D

 

Docs is a straight talking guy and extremely helpful to memebers, he's very adept and always keen to share.  He was just calling it as he see's it. It's all good :cool:



#26 Fatdog

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Posted 05 January 2017 - 11:14 AM

As a Brit, that was clean.

Sometimes some people just need telling but I am happy to see resolutions to problems like these from those that know, if indeed there is such a person :)

I agree.  It is a pity to have a member, who supposedly knows how to fix the problem, to not give any help in the thread.

 

However, the terse, non-helpful "suggestions" should have been addressed months ago when the thread was more relevant.



#27 docs

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Posted 05 January 2017 - 11:44 AM

Agreed and thanks. Lets hope we can get a proper resolution posted before it gets locked. Cheers.

Max?

#28 Superduper

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Posted 07 January 2017 - 12:16 AM

Ok, I'll just say it. The problem is the NE649 Dolby chips. This is "The Fix" to this problem which is very common on Panasonic models. Each channel has its own chip so if only 1-channel is dead, you can confirm by swapping them from side to side. However, you should only attempt this if you have sufficient soldering skill and appropriate equipment to desolder the chips without damaging them, and better still, install IC sockets so that the chips can be reinstalled without further heating shock. This also allows simple replacement if the chip is confirmed bad.

#29 docs

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Posted 07 January 2017 - 03:45 AM

Thanks Norm, this will help countless people in the future.

#30 toshik

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Posted 07 January 2017 - 09:51 AM

 

I agree.  It is a pity to have a member, who supposedly knows how to fix the problem, to not give any help in the thread.

 

 

However, the terse, non-helpful "suggestions" should have been addressed months ago when the thread was more relevant.

 

 

I'm sorry guys but upon registering at this forum, I did not see any obligations on sharing any info.

Topic starter was going the wrong directing I was trying to guide him in the right direction this is all. What is bad about guiding the person in the right direction? 

Bitching about not giving out the information and immediatey jumping into personal comments about me is AT LEAST not nice and should not be tolerated by the moderator. Example: there is another fellow on the forum selling clings for RX series I did not see anyone complaining about him not giving clings away for free to another members :-) 

Anyone who does not like something can feel free to purchase RX-5350 boombox, scope, meters and whatever else needed, spend a few weeks finding the solution and post it here - this would make everyone happy I guess!

 

I checked all my posts asking for help and MOST of them ended up with me finding the solution myself.

 

I am trying to be as reasonable as possible and I should say that mr. Superduper WAS always very nice helpful in all technical matters to me, so his post surprised me quite a bit since I was the one who told him about the faulty Dolby chips! Taking credit for someone else is not nice, I tried to PM him on this first but sadly his PMs are locked, so I post it here.

 

One more thing - moderator please lock the thread I don't want to see more insults here. 

If anyone feels I don't need to stay here anymore since I'm not making everyone completely happy I'd cancel my membership right away.