Operation Sanyo M9998!

[BoomboxLover48]

Finally after a long wait I started working on my Sanyo M9998.

From the way the PC boards are positioned in the unit I wanted to try the easiest way to reach the deck section. When I tried before it seemed really hard to reach the deck section. Today I found a much easier way to reach the deck section for belt replacement.

I need to confirm the belt sizes for M9998.

I hope the following is correct: FRW10.1, SCX8.6, SCY5.2, SCY7.0


Pictures and more details to follow.

 

[BoomboxLover48]

The belt sizes don't make sense when I check with the old belts on it.

I was wondering if anyone has the correct belt sizes!

 

[baddboybill]

I think Scott has changed belts on these but not sure he even remembers sizes.

 

[BoomboxLover48]

I think Scott has changed belts on these but not sure he even remembers sizes.

Thank you Bill!

I had a spare M80 main flat belt and that came handy. I found other square belts in my rubber square belts set bought from Ebay.

Just finished putting all the belts. Now I have to put the boards and all in the right places and chassis in the box.

 

[BoomboxLover48]

Operation was successful but patient is in a coma!

I replaced the belts and deck works fine but now no audio from the radio, line in or tape. I could have messed up something on this M9998.

When you increase the volume there is no effect. I could see that this box was previously tampered with. Missing screws. Power input male 4 pin connector was replaced very unprofessionally. Record button key was broken at the base.

I hear a loud static when I turn the power on and it fades away. I am pretty sure I didn't miss any connections on the 9998.

I opened up it again to check it one more time. No luck yet! I think I need to leave it aside for a while and work on it later.
I can see the FM tuning in but no sound. Function switch flipping has no effect.

I have worked on so many different boxes and this is the first time I am getting into a situation like this.

Altogether I spend 10 hours on it.


What a nightmare!

 

[jimmyjimmy19702010]

I hope you didn't accidentally connect the power cable that runs from the transformer to the amp output connector momentarily. You can very easily connect power into the amp output connector as the plugs have the same number of pins and the cables are long enough to be connected incorrectly.

Hopefully it's something else!

 

[BoomboxLover48]

I hope you didn't accidentally connect the power cable that runs from the transformer to the amp output connector momentarily. You can very easily connect power into the amp output connector as the plugs have the same number of pins and the cables are long enough to be connected incorrectly.

Hopefully it's something else!

Hi JImmy, No not at all. The power connection is at the right lower corner when you view from the back side. I didn't make that mistake. The output is at the top that is all tucked in there at the top barely reaching the tweeter and all. It is so hard to pull it down and connect at the bottom right corner.


When I turn the input volume up I can hear the Hssshhh!! static response, but nothing when I turn the volume up.

When I bring my hand near the 4 pin connectors next to the output connector, I hear loud audio. The same way once you bring your fingers near line in section of an amp.

It could be something else. I cleaned the record bar switch and the deck switches at the bottom. I was so happy when I put new belts, but this issue with no sound from line in /radio / tape was a total surprise to me.

~ Royce

 

[jimmyjimmy19702010]

Tone board is connected?

 

[BoomboxLover48]

Tone board is connected?

Oh my! That could be a possibility! Good thought James!

Is there a plug connector for it? I remember pulling one out in the disassembly process, and then checked all around.... found none!

That connector I might have pulled out to separate the main amp board to get more room to work on the deck.

No wonder it had no effect on volume or anything except for the input volume pot. That works for some reason!

 

[jimmyjimmy19702010]

From memory, there are 1 or maybe 2 connectors for the 'standalone' tone board.

 

[BoomboxLover48]

I think I need to open up and check if I miss any connectors under the amp board.

From memory, there are 1 or maybe 2 connectors for the 'standalone' tone board.

I was separating the main board to get more room to access the deck cover and all. Basically the top board was separated more at the lower section and don't remember disconnecting connectors. I had to cut some plastic ties and that was it. At that point I was a bit distracted, so don't know if I disconnected anything in between the main board with the amp IC and all from the rest.

I will open it all up tomorrow and look more carefully.

 

[jimmyjimmy19702010]

It's gotta be something simple - you'll get it going.

 

[BoomboxLover48]

It's gotta be something simple - you'll get it going.

Thanks James! I hope so.

 

[Superduper]

The tuner and amp PCB's mate with interlocking connectors. They are easy to mis-align when disconnected for access and subsequently placed back together. In fact, it's easy to miss them entirely.

 

[BoomboxLover48]

The tuner and amp PCB's mate with interlocking connectors. They are easy to mis-align when disconnected for access and subsequently placed back together. In fact, it's easy to miss them entirely.

Thanks Norm!

I will look into it soon.

 

[baddboybill]

Hope you find issue Royce

 

[BoomboxLover48]

Hope you find issue Royce

Thanks Bill! I will work on it today!
I became an expert to open it and take all apart, but learning damage control.
I am extra careful not to tamper with anything, and believe it is something simple like a connector.

 

[BoomboxLover48]

Fixed it!

Thank you James, Norm and Bill!

The connector to the tuning board was misaligned! I checked it first and later while adjusting for the mounting holes it got disengaged, I might have lifted the top section!

I will add lots of pics in a day or two so other members can easily work on the belt replacement without trouble.

 

[Fatdog]

Super yay!!

 

[superlew]

Nice work Royce!

I was thinking along the lines of Norm's suggestion but, having never seen or worked on one, I didn't want to give a bad tip.
I've missed or mis-aligned a million pin connectors over the last several years. Of course, they've all been corrected.