Bad luck with Sanyo M9998!

I bought one Sanyo M9998 from a trusted member here and that got all sorts of issues. The worst was right speaker sounds like rattling and seems the speaker is going to die. It could be a problem with the channel also because right side lacks enough bass.

Finally the second one I have is pretty good cosmetically and sounds fantastic. It also needs new belts.

This unit got the following issues.

1. When I press the light switch there is no green light
2. AM doesn't work. I cleaned the band switch and all switches well except the record switch.
3. FM light doesn't come on and only light up and play with stereo reception if I play with the mono/stereo/wide switch flip quickly to wide mode when FM is tuned well. But when the stereo light is on if you try to tune out and bring it back it loses the stereo reception and LED also turns off. To get it back I have to move the mono/stereo/wide switch flip quickly to wide mode again.


If I can get the stereo tune in feature working I will be very happy. Any help and suggestions with this is greatly appreciated.

I cleaned the function switches and all switches at the back including internal speaker/ external speaker switch and all.

I also need an original antenna for this unit. Please PM me if you got one to spare.

Did you buy the second one off some guy in Florida? Because it sounds exactly like one I sold on Ebay a year or two ago.

No! This was bought locally from an older gentleman who never used it for many years.

I might have the antenna and base for you.

I send you a PM Joe!

Box is mint so if I find it hard to repair I am keeping it for line in use.
Just love the sound of it! Very unique!
Now I opened it up and saw one wire with a cap disconnected. I could see another one with the same value grounded on one of the anchoring screws to the metal frame.

I can't find the place where it is connected to...
The lower part of the yellow wire is disconnected..

Plop plop fizz fizz

Sanyo radio tuners often go bad over time. It's either that or just a dirty contact. Hopefully it's the latter.

blu_fuz said:

Plop plop fizz fizz

image.jpg

Click to expand...

Thanks Joe! I really appreciate your help. Please ship it at your convenience.

Reli said:

Sanyo radio tuners often go bad over time. It's either that or just a dirty contact. Hopefully it's the latter.

Click to expand...

It went through a good contact cleaning procedure by squirting in those top holes over the switch and working it several times.
This is not a user friendly box design at all. If not I would have took it all apart and cleaned it well.

I am obsessed with the sound quality of this box and I am afraid this would become my fav box after having more than 130 of them including many high end ones.

I don't care if the cassette needs belts and all but what really bothers me is that I cannot tune in and FM stereo station without playing with the mono/stereo/wide flip switch.

In the worst case I will keep it for line in listening. The sound is just amazing!

So you pulled the chassis to clean the switches etc? You must have because you can't clean the switches without the chassis out of the front case.

My M7900K has exactly the same issues with the FM stereo light - having to flip the mono/stereo switch back and forth to lock in the stereo light and then having to do the same thing if you change stations.

Your other one with the weak channel needs a recap - very common with the M9998. The caps are only rated for 5000 hrs of use - I think because the M9998s sounded so good they got a lot of use over the years and many have simply worn themselves out! I've gone through 3 of these M9998s to finally find a fully working one with great sound.

The deck on my 3rd and final M9998K had a new, high end tape head fitted and was fully serviced, lubed etc and it is simply the best sounding deck I've heard - it even makes my old 80s tapes sound crisp and clear - no other box I've heard can do that!

James...

I

BoomboxLover48 said:

It went through a good contact cleaning procedure by squirting in those top holes over the switch and working it several times.
This is not a user friendly box design at all. If not I would have took it all apart and cleaned it well.

I am obsessed with the sound quality of this box and I am afraid this would become my fav box after having more than 130 of them including many high end ones.

I don't care if the cassette needs belts and all but what really bothers me is that I cannot tune in and FM stereo station without playing with the mono/stereo/wide flip switch.

In the worst case I will keep it for line in listening. The sound is just amazing!

Click to expand...

According to Norm there's a transistor that goes bad on Sanyo tuners. It causes weak reception, and eventually no reception at all.

Does yours have any problems pulling in stations? Number of stations, strength? If so, that's the problem.

But if the only problem is the stereo switch, then that's probably just a contact issue.

BTW is this a K model or the regular model? I ask because my 9998 sounded better than my 9998K for some reason, even though the K has been recapped. I assume the speakers are identical, right?

The main speakers are identical apart from the different centre cap as far as I know (viewing the back of both speakers in pics). The tweeters are identical.

jimmyjimmy19702010 said:

The main speakers are identical apart from the different centre cap as far as I know (viewing the back of both speakers in pics). The tweeters are identical.

Click to expand...

That's what I assumed too. But there was this one dude who claimed a few years ago that the 9998's woofer surrounds were more flexible and thus could produce warmer bass than the K model. But I don't see why Sanyo would have used different materials on the K and non-K.

jimmyjimmy19702010 said:

So you pulled the chassis to clean the switches etc? You must have because you can't clean the switches without the chassis out of the front case.

My M7900K has exactly the same issues with the FM stereo light - having to flip the mono/stereo switch back and forth to lock in the stereo light and then having to do the same thing if you change stations.

Your other one with the weak channel needs a recap - very common with the M9998. The caps are only rated for 5000 hrs of use - I think because the M9998s sounded so good they got a lot of use over the years and many have simply worn themselves out! I've gone through 3 of these M9998s to finally find a fully working one with great sound.

The deck on my 3rd and final M9998K had a new, high end tape head fitted and was fully serviced, lubed etc and it is simply the best sounding deck I've heard - it even makes my old 80s tapes sound crisp and clear - no other box I've heard can do that!

James...

Click to expand...

Hi James,

Thanks for the valuable input!

I didn't pull out the chassis yet but could reach all the switches top with the two holes on it to squirt Deoxit through it. That is all what I did so far. I presume it should have got inside to clean the contacts.

The reception is astounding! Pulls in all stations I can think of and sounds crystal clear.

I am waiting for the deck repair when I have some time. All I did was squirting deoxit from the top of sliding switches and work it through.

"I bought one Sanyo M9998 from a trusted member here and that got all sorts of issues. The worst was right speaker sounds like rattling and seems the speaker is going to die. It could be a problem with the channel also because right side lacks enough bass."

• Not sure what is the reason for mentioning the "trusted" member thing. Either you knew the unit had issues in which case, the "trusted member" part is irrelevant or didn't know and felt it was misrepresented in which case, that comment merely leads us to speculate who it was. Frankly, I guess I don't wanna know since I'm not especially fond of beat around the bush and guess so I'll stick to the issues. In this case, so many possibilities it's probably better to just say it needs to be looked into by someone willing to spend the time to diagnose it hands on.

--------------------------------------------------------------------------------------------------

This unit got the following issues.

"1. When I press the light switch there is no green light."

• What can I say.... either the bulb burned out, or the transformer dedicated lamp winding burned out (this model utilizes a transformer with a special dedicated winding used only by the bulb), or someone swapped out the transformer for one without the dedicated winding (you won't find a replacement with that special winding) or there is a broken connection, or the switch is bad. There are 5 possible ways to switch on the bulb. 1-the power switch when on AC, 2- the light switch when on DC (or AC), 3-Play button, 4-FF button, 5-RW button. That's something you need to check for yourself.

"2. AM doesn't work. I cleaned the band switch and all switches well except the record switch."

• Could be the AM RF amp burned out which is fairly common on Sanyos since the transistors they used are not as durable over time; or could be failure in the AM local oscillator or mixer circuit, or less likely the IF amplifiers; and of course the all-on-one qualifier: any number of things. Typically, if you are getting very quiet AM, the issue is most likely in the IF stages or if the issue is no AM but you do get white noise, the RF section.

"3. FM light doesn't come on and only light up and play with stereo reception if I play with the mono/stereo/wide switch flip quickly to wide mode when FM is tuned well. But when the stereo light is on if you try to tune out and bring it back it loses the stereo reception and LED also turns off. To get it back I have to move the mono/stereo/wide switch flip quickly to wide mode again."

• Most commonly, the 19khz VCO adjustment is off. This leads to difficulty capturing and locking stereo. Flipping the switch sometimes strengthens the signal momentarily enough to "lock" the signal. Once "locked" the system can maintain lock until it drifts off. Adjustment of that circuit is the most likely fix. On the M9998, adjust SVR501. On the M9998K, adjust the trimpot labeled VCO. Center the trimpot for best possible result within the range when tuned to a MPX station. This will get you close but isn't the best way. Better to use a frequency counter and adjust at a weak or dead spot near the center of the dial, and adjust until reading at test point centers at 19khz, this ensures that strong and weak stations alike get best MPX signal capture and locking.

"Finally the second one I have is pretty good cosmetically and sounds fantastic. It also needs new belts."

• Well, it's been discussed before that you earn your money rebelting this model. It is definitely a frustrating endeavor for the undedicated, especially if it's your first time. Also once you take apart the looms and unwind all the cables necessary to get access, restoring all the looms as before to their proper size/location is very difficult. However, if you don't get those cables back to exactly where they belong, it's almost impossible to get the back cover to mate back without interference. Oh, and the belt on this model is very exacting. I don't know the proper size but this is another of those models without a motor speed adjustment so the belt size is critical. Too loose and the quasi servo operation won't work right and too tight and the speed will drag. Since this motor needs to quickly spool up the assembly in order to leverage the heads up, it requires a lot of torque and it's unclear if the smaller "standard" motor, the ones with the internal speed adjusters, will work as replacements or not.

Reli said:

I



According to Norm there's a transistor that goes bad on Sanyo tuners. It causes weak reception, and eventually no reception at all.

Does yours have any problems pulling in stations? Number of stations, strength? If so, that's the problem.

But if the only problem is the stereo switch, then that's probably just a contact issue.

BTW is this a K model or the regular model? I ask because my 9998 sounded better than my 9998K for some reason, even though the K has been recapped. I assume the speakers are identical, right?

Click to expand...

Hi Reli,

Thanks for the valuable input!

It pulls stations so well and crystal clear. It is the black dust cap regular model.

I believe I have to take it all apart and do an extensive cleaning. I was squirting from the top of the sliding switches so far and on some I went from the ends.

[SIZE=9pt]Superduper, on 07 Jun 2015 - 7:45 PM, said:[/SIZE]





[SIZE=10.5pt]Norm, I fell of my chair reading this detailed and descriptive reply! Wow! Thanks so much! [/SIZE][SIZE=10.5pt] [/SIZE]


[SIZE=9pt]"I bought one Sanyo M9998 from a trusted member here and that got all sorts of issues. The worst was right speaker sounds like rattling and seems the speaker is going to die. It could be a problem with the channel also because right side lacks enough bass."[/SIZE]
[SIZE=10pt]· [/SIZE][SIZE=9pt]Not sure what is the reason for mentioning the "trusted" member thing. Either you knew the unit had issues in which case, the "trusted member" part is irrelevant or didn't know and felt it was misrepresented in which case, that comment merely leads us to speculate who it was. Frankly, I guess I don't wanna know since I'm not especially fond of beat around the bush and guess so I'll stick to the issues. In this case, so many possibilities it's probably better to just say it needs to be looked into by someone willing to spend the time to diagnose it hands on.[/SIZE]
[SIZE=9pt]The only reason to mention it was because my love for this box started from that one and wanted a good working one, Also I can use this one for parts, The radio works fine on the first one,[/SIZE]

[SIZE=9pt]--------------------------------------------------------------------------------------------------[/SIZE]

[SIZE=9pt]This unit got the following issues. [/SIZE]

[SIZE=9pt]"1. When I press the light switch there is no green light."[/SIZE]
[SIZE=10pt]· [/SIZE][SIZE=9pt]What can I say.... either the bulb burned out, or the transformer dedicated lamp winding burned out (this model utilizes a transformer with a special dedicated winding used only by the bulb), or someone swapped out the transformer for one without the dedicated winding (you won't find a replacement with that special winding) or there is a broken connection, or the switch is bad. There are 5 possible ways to switch on the bulb. 1-the power switch when on AC, 2- the light switch when on DC (or AC), 3-Play button, 4-FF button, 5-RW button. That's something you need to check for yourself.[/SIZE]
[SIZE=9pt]I will check it soon! Sadly it didn't turn on play, FF or RW.[/SIZE]

[SIZE=9pt]"2. AM doesn't work. I cleaned the band switch and all switches well except the record switch." [/SIZE]
[SIZE=10pt]· [/SIZE][SIZE=9pt]Could be the AM RF amp burned out which is fairly common on Sanyos since the transistors they used are not as durable over time; or could be failure in the AM local oscillator or mixer circuit, or less likely the IF amplifiers; and of course the all-on-one qualifier: any number of things. Typically, if you are getting very quiet AM, the issue is most likely in the IF stages or if the issue is no AM but you do get white noise, the RF section.[/SIZE]
[SIZE=10pt]· [/SIZE][SIZE=9pt]Oh my! I never thought these have issues like that.[/SIZE]



[SIZE=9pt]"3. FM light doesn't come on and only light up and play with stereo reception if I play with the mono/stereo/wide switch flip quickly to wide mode when FM is tuned well. But when the stereo light is on if you try to tune out and bring it back it loses the stereo reception and LED also turns off. To get it back I have to move the mono/stereo/wide switch flip quickly to wide mode again."[/SIZE]
[SIZE=10pt]· [/SIZE][SIZE=9pt]Most commonly, the 19khz VCO adjustment is off. This leads to difficulty capturing and locking stereo. Flipping the switch sometimes strengthens the signal momentarily enough to "lock" the signal. Once "locked" the system can maintain lock until it drifts off. Adjustment of that circuit is the most likely fix. On the M9998, adjust SVR501. On the M9998, adjust the trimpot labeled VCO. Center the trimpot for best possible result within the range when tuned to a MPX station. This will get you close but isn't the best way. Better to use a frequency counter and adjust at a weak or dead spot near the center of the dial, and adjust until reading at test point centers at 19khz, this ensures that strong and weak stations alike get best MPX signal capture and locking.[/SIZE]
[SIZE=10pt]· [/SIZE][SIZE=9pt]I will work on it soon! I am still learning this box so congested inside. It is a nightmare to look for issues. I need to find some time to take it apart and have a good look at it. I'm so busy with work and travel. I need to find some time in between.[/SIZE]

[SIZE=9pt]"Finally the second one I have is pretty good cosmetically and sounds fantastic. It also needs new belts."[/SIZE]
[SIZE=10pt]· [/SIZE][SIZE=9pt]Well, it's been discussed before that you earn your money rebelting this model. It is definitely a frustrating endeavor for the undedicated, especially if it's your first time. Also once you take apart the looms and unwind all the cables necessary to get access, restoring all the looms as before to their proper size/location is very difficult. However, if you don't get those cables back to exactly where they belong, it's almost impossible to get the back cover to mate back without interference. Oh, and the belt on this model is very exacting. I don't know the proper size but this is another of those models without a motor speed adjustment so the belt size is critical. Too loose and the quasi servo operation won't work right and too tight and the speed will drag. Since this motor needs to quickly spool up the assembly in order to leverage the heads up, it requires a lot of torque and it's unclear if the smaller "standard" motor, the ones with the internal speed adjusters, will work as replacements or not.[/SIZE]
[SIZE=10pt]· [/SIZE][SIZE=9pt]It looks very complicated. I’ve worked on many boxes and this is a tough deal. I know I can do it but don't know when.[/SIZE]

BoomboxLover48 said:

Hi James,

Thanks for the valuable input!

I didn't pull out the chassis yet but could reach all the switches top with the two holes on it to squirt Deoxit through it. That is all what I did so far. I presume it should have got inside to clean the contacts.

The reception is astounding! Pulls in all stations I can think of and sounds crystal clear.

I am waiting for the deck repair when I have some time. All I did was squirting deoxit from the top of sliding switches and work it through.

Click to expand...

Spraying the top rocker switches would have done the job. However, the pots can't be sprayed until you pull the chassis. Here is the removable pots board. Some people think the small hole behind the band selector and volume knobs gives access for spraying cleaner. Unfortunately, the holes don't line up with the pots:View attachment 19133View attachment 19132

jimmyjimmy19702010 said:

Spraying the top rocker switches would have done the job. However, the pots can't be sprayed until you pull the chassis. Here is the removable pots board. Some people think the small hole behind the band selector and volume knobs gives access for spraying cleaner. Unfortunately, the holes don't line up with the pots:

image.jpg

image.jpg

Click to expand...

James,

I didn't get that far. All I did was open the back cover and spray the rocker switches with Deoxit through the top two holes on each of them and work it out.

Rotary controls show no issues but still I will clean them when I have time to work on this box.

Line in is PERFECT sounding!