trueno92
Active Member
Hi All,
OK I am creating this thread with the intent to consolidate all the known info on the MSM5540 chip and replacing it.
I am new to this, and in everything i know so far, has been read and mainly collected from AUDIOKARMA, so I hope this can give back to this wonderfully knowledgeable community of hobbyists!
THE CULPRIT
In an age that FM radio has more competition than ever for streaming music/radio shows, I found FM on these vintage Sansui units very refreshing. Maybe it was because it can flawlessly pull in every station under the sun! I don't think I have ever owned an FM tuner of any credible mention and this really surprised me. The number of stations and the clarity was new to me.
But to look at the handsome unit, was just glaring back with a black-eye:
Yup, the digits and quartz lock were non-functional.
Although cosmetic and not affecting the performance of my tuner, I wanted to repair this back to its former glory. Hey, I got into vintage gear for the ability to fix whatever I could!
THE CULPRIT:
My unit has the F3220 display board. You may have the F3000. I noticed that the F3220s are in the units with the non-chamfered heatsinks on the back and from my sample of pics on the net, the F3220 are mainly in production with 1980 serial numbers.
NOTE D05 in the center of the picture. SHOULD THERE BE SOMETHING HERE???
REMOVAL:
Pretty straight forward. Braid and the iron working 2-3 pins at a time. I found this easier than cutting each pin from the IC and working those out. Once the chip is free it simply falls out
(IF THIS IS NOT BEST-PRACTICE FOR IC REMOVAL, PLEASE REPLY TO THIS THREAD AND I WILL CORRECT THIS SECTION)
and old chip out, perfectly usable condition
NEW IC. OLD IC
SOCKET INSTALLED
(TESTED, works)
NEW CHIP INSTALLED
I later revised this to add: USE another 40 pin socket on your new M5540 chip. If you have to troubleshoot your work, it will be easier on the chip as you don't have to worry about bending pins. So basically you will be add a socket to the board and another socket to the chip.
My system now has the quartz lock feature and it works perfect, however my digits still don't read correct now locked at 167.6 on AM and FM.
I checked the tuning pot in the service manual for step 5 of the FM tuner calibration but it highlights adjusting TC06 on the front-end (which i learned later is the actual FM moving tuner meat slicer thing). ON my 6700, this did not correct the digits, but instead worked more to calibrate the actual tuner to the scale...
SERVICE MANUAL SAYS:
NOW WHAT DOES THAT FIRST INSTRUCTION MEAN???
"... make the dial pointer go round the dial scale at once by turning knob"
I assumed this to be, run the dial pointer completely across the scale from beginning to end
And this is what I got for locating TC06
6th entry down on the right side
I am hoping you experts can assist me on this!
OK I am creating this thread with the intent to consolidate all the known info on the MSM5540 chip and replacing it.
I am new to this, and in everything i know so far, has been read and mainly collected from AUDIOKARMA, so I hope this can give back to this wonderfully knowledgeable community of hobbyists!
THE CULPRIT
In an age that FM radio has more competition than ever for streaming music/radio shows, I found FM on these vintage Sansui units very refreshing. Maybe it was because it can flawlessly pull in every station under the sun! I don't think I have ever owned an FM tuner of any credible mention and this really surprised me. The number of stations and the clarity was new to me.
But to look at the handsome unit, was just glaring back with a black-eye:
Yup, the digits and quartz lock were non-functional.
Although cosmetic and not affecting the performance of my tuner, I wanted to repair this back to its former glory. Hey, I got into vintage gear for the ability to fix whatever I could!
THE CULPRIT:
My unit has the F3220 display board. You may have the F3000. I noticed that the F3220s are in the units with the non-chamfered heatsinks on the back and from my sample of pics on the net, the F3220 are mainly in production with 1980 serial numbers.
NOTE D05 in the center of the picture. SHOULD THERE BE SOMETHING HERE???
REMOVAL:
Pretty straight forward. Braid and the iron working 2-3 pins at a time. I found this easier than cutting each pin from the IC and working those out. Once the chip is free it simply falls out
(IF THIS IS NOT BEST-PRACTICE FOR IC REMOVAL, PLEASE REPLY TO THIS THREAD AND I WILL CORRECT THIS SECTION)
and old chip out, perfectly usable condition
NEW IC. OLD IC
SOCKET INSTALLED
(TESTED, works)
NEW CHIP INSTALLED
I later revised this to add: USE another 40 pin socket on your new M5540 chip. If you have to troubleshoot your work, it will be easier on the chip as you don't have to worry about bending pins. So basically you will be add a socket to the board and another socket to the chip.
My system now has the quartz lock feature and it works perfect, however my digits still don't read correct now locked at 167.6 on AM and FM.
I checked the tuning pot in the service manual for step 5 of the FM tuner calibration but it highlights adjusting TC06 on the front-end (which i learned later is the actual FM moving tuner meat slicer thing). ON my 6700, this did not correct the digits, but instead worked more to calibrate the actual tuner to the scale...
SERVICE MANUAL SAYS:
NOW WHAT DOES THAT FIRST INSTRUCTION MEAN???
"... make the dial pointer go round the dial scale at once by turning knob"
I assumed this to be, run the dial pointer completely across the scale from beginning to end
And this is what I got for locating TC06
6th entry down on the right side
I am hoping you experts can assist me on this!
Last edited: