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Operation Sanyo M9998!


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#1 BoomboxLover48

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Posted 03 January 2017 - 02:39 PM

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. 

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#2 BoomboxLover48

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Posted 03 January 2017 - 07:03 PM

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! :blink:



#3 baddboybill

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Posted 03 January 2017 - 08:21 PM

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

#4 BoomboxLover48

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Posted 03 January 2017 - 10:58 PM

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. 



#5 BoomboxLover48

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Posted 04 January 2017 - 02:32 PM

Operation was successful but patient is in a coma! :blink:  :blush:

 

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.  :bang:  :bang:  :bang:

 

 

What a nightmare!



#6 jimmyjimmy19702010

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Posted 04 January 2017 - 03:02 PM

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!

#7 BoomboxLover48

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Posted 04 January 2017 - 05:07 PM

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



#8 jimmyjimmy19702010

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Posted 04 January 2017 - 05:26 PM

Tone board is connected?

#9 BoomboxLover48

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Posted 04 January 2017 - 06:42 PM

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! :hmmm:  :no:

 

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!



#10 jimmyjimmy19702010

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Posted 04 January 2017 - 07:42 PM

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

#11 BoomboxLover48

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Posted 04 January 2017 - 07:58 PM

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. 

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#12 jimmyjimmy19702010

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Posted 04 January 2017 - 08:30 PM

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

#13 BoomboxLover48

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Posted 04 January 2017 - 09:23 PM

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

Thanks James! I hope so. 



#14 Superduper

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Posted 04 January 2017 - 09:50 PM

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.



#15 BoomboxLover48

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Posted 04 January 2017 - 10:23 PM

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. 



#16 baddboybill

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Posted 05 January 2017 - 01:16 AM

Hope you find issue Royce

#17 BoomboxLover48

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Posted 05 January 2017 - 09:05 AM

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.



#18 BoomboxLover48

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Posted 05 January 2017 - 11:18 AM

Fixed it! :thumbsup:

 

Thank you James, Norm and Bill! :bow:  :bow:  :bow:

 

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.

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#19 Fatdog

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Posted 05 January 2017 - 11:23 AM

Super yay!!  :clap:



#20 superlew

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Posted 05 January 2017 - 11:56 AM

Nice work Royce! :thumbsup:

 

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. :lol:



#21 BoomboxLover48

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Posted 05 January 2017 - 12:52 PM

Nice work Royce! :thumbsup:

 

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. :lol:

Thanks Arom!

 

This unit has so many connectors and few ribbon lines also. I was very careful not to flex those ribbon lines which are prone to damage. Once you disconnect the connectors a few times it becomes so easy to know where it all belongs. I numbered them from left to right using tape, also took pics. I saw this main lead connector from amp board to tuner board only when I lifted the main board. I then made sure it was there when I put is back. My bad! :bang:  

 

Next time push that connector mounted on both boards, hold it in position, and put the top screw for the board. Then the lower screws to hold the main PC board of the amp.

 

For some reason wires came in the way and I might have accidentally lifted the board only to disconnect it. It doesn't take much to disconnect the line to the tone board.

 

This was a good learning experience! There is no need to remove soldered connections at all. One can easily replace belts from the lower section by lifting the main amp board and use foam pieces in a ziplock bag as a wedge. 



Super yay!!  :clap:

Thanks Bobby! Lessons learned from mistakes! 

I am glad we have very helpful members here. :bow:  :bow:



#22 BoomboxLover48

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Posted 05 January 2017 - 01:51 PM

Here are some pics....

 

Take pictures as you disassemble.

 

Disconnect power cord. Remove all the knobs from the front. Open the cassette door, leave it open.

 

Remove all the back cover screws. Two are hidden in the cassette compartment.

Gently pull out the rear cover because there are several connectors and wire pins to remove.

 

Looking from the top take pictures of these connectors and mark them.

 

Antenna connectors and two yellow wire connectors can be easily pulled out holding on the PC board.

On the top right corner you can see the speaker wire 4 pin connector, unplug it.

 

Once all the connectors from the rear cover top area is removed , lay the rear cover on it's back.

 

The power lead 4 pin connector goes to the right bottom corner, unplug it.

Now the rear cover can be separated from the front.

Now we are ready for the chassis removal.

On the right side under the speaker a small PC board needs to be removed before taking the chassis out.

Lift the top push buttons and rotate one clockwise and the other anti clockwise, they will stay up locked in a slot. This step is very important or else will break the switches.

Chassis mounting screws can be seen along the rim of the chassis. Once they are all removed chassis will come out easily. Take care not to hold any area of it where the tuning cord is running, also on the tuning wheel gang assembly.

By moving wires around it it can be positioned on a micro fiber cloth buttons and dial plate facing down.

Now start working on partially moving/separating the main board up to get access for belt replacement.

 

The PC board with cassette controls next to the motor is mounted on a steel plate. This plate is mounted on the metal frame with two small screws. It is a bit of struggle to find the right Philips screw driver tip to unscrew them.

 

There are white plastic pin tips on the head of the cassette function switches. These plastic tips will fall backwards. There tips need to be re positioned before putting it back. 

Before one removes the mounting screws of the mail amp board this cassette control board has to be removed from the metal chassis.

There are several plastic ties securing wire bundles on the side of the main amp board. Untie them before lifting the board slightly up. Lift the main PC board gently and separate like 3 inches.

Use a foam wedge to keep it separated to gain access to the cassette flywheel cover area.

The lower sections of the deck are is now clearly visible.

Two screws hold the flywheel cover. The flywheel cover can be easily removed, but watch the belt guide on it. The new belt has to channel through that cut section on the side of the flywheel cover.

There are altogether 3 belts there to replace. The smallest square belt goes from the small axis pulley of the flywheel to a small plastic pulley. The main flat belt goes from the motor pulley to the flywheel. The other belt connects the middle part of the flywheel to another almost same size plastic pulley.

It is a little tricky to get these belts in position starting with the main flat belt. I used plastic tools to put those belts in place.

Counter small square belt is ~8.0”

I will post belt sizes later.

 

I have more...

Attached Files



#23 caution

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Posted 05 January 2017 - 04:31 PM

Congrats on bringing this back from the dead! :clap:  I knew you would take lots of notes, even then you can miss something.

On complex innards like this one it's so important to write down a note every time you unplug/remove something.

Can't wait to see it back together!



#24 baddboybill

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Posted 05 January 2017 - 04:36 PM

Awesome!!! It's so great when a big issue actually is only something small ;-)

#25 BoomboxLover48

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Posted 05 January 2017 - 05:43 PM

Awesome!!! It's so great when a big issue actually is only something small ;-)

Exactly! Thanks Bill! 

 

Now I have lots and lots of additional pictures to share if another member needs help.



 



Now I noticed that the dishonest seller didn't say anything about one bad speaker and missing reel drive axle tips (cogs). Yuck!

 

I need to find the reel tips and also a speaker for this M9998. 

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#26 BoomboxLover48

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Posted 05 January 2017 - 06:28 PM

The reel axle (cog) missing is a big issue!

 

I just saw this nice thread.

 

http://boomboxery.co...table-assembly/



Congrats on bringing this back from the dead! :clap:  I knew you would take lots of notes, even then you can miss something.

On complex innards like this one it's so important to write down a note every time you unplug/remove something.

Can't wait to see it back together!

Hi Eric, It was a good learning experience! 

 

Now I have to design a cog that can snug fit on the drive axles. 

 

I will come up with a solution to it.



#27 Hisrudeness

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Posted 06 January 2017 - 02:30 PM

Well done Royce.
Sounds like you're almost there..

#28 MyOhMy

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Posted 06 January 2017 - 02:45 PM

As much as I like this box I do have a question that's starting to play on my mind somewhat:  Is this particular box the complex nightmare to work on it looks to be? 



#29 T-STER

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Posted 06 January 2017 - 03:12 PM

The reel axle (cog) missing is a big issue!

 

I just saw this nice thread.

 

http://boomboxery.co...table-assembly/

 

I had the same issue mate, I ended up taking the spindles from an Aiwa 950 parts box i had (the deck was long since fubar) as they were incredibly similar and in great shape, plays perfect.

 

I keep decks from any parts box i find and buy them in any shape at bootsales just for aerials/decks/buttons etc so i have quite a spares box, if you have any trouble finding them let me know, i'll compare my spares to my 9998 and find a suitable set and send em to you.



#30 Reli

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Posted 06 January 2017 - 04:29 PM

Excellent thread!