Vinnie Stu
New Member
I could use some help. i am getting no AM at all no sound or static. also no FM stereo light the bulb is good, all stations come in well.
Help sansui 9090db No AM at all nothing also no FM stereo
- Thread starter Vinnie Stu
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So you have no AM at all but you receive FM and can tune stations but the stereo light doesn't illuminate? You have two separate problems. AM not working may be as simple as a dirty mode switch. The Stereo light will require a little digging. How did you check the "bulb" to know it's good? You can test the control for the bulb with a DC voltmeter. Put the probes across the bulb and dial across a strong FM stereo station. The meter should deflect when your signal strength and tune centering meters indicate you are on the station.
Also be sure the tuner power supply voltage is where it should be. Measure the DC voltage between chassis ground and Pins 1 and 2 on the power supply board F-2619. It's the one that gets hot on the left side of the tuner board.
- Pete
Also be sure the tuner power supply voltage is where it should be. Measure the DC voltage between chassis ground and Pins 1 and 2 on the power supply board F-2619. It's the one that gets hot on the left side of the tuner board.
- Pete
Vinnie Stu
New Member
Thanks Pete i checked the stereo bulb using a 9volt battery. what should the f-2619 voltage be set at can not find the spec's in the service manual. Here is a run down on the unit.
I got the unit from my next door neighbor it's was in his garage for over 30 years in the original box (box kind of beat up but original none the less).
Connected to DBT and would not come out of protection mode F-2624 Driver Board and found 4 fuse resistors open. Replaced all fuse resistors and came out of protection mode and then rebuilt the board.
Rechecked the unit no output from either channel comming out of the F-2655 Dolby board only left channel signal going in to the board with no output. Traced right channel signal loss to broken trace on
the F2653 Eq/selector switch board repaired the broken trace with jumper wire. Rebuilt F2653 and checked and cleaned all wafers on the selector switch. now i have left and right signal going into Dolby board with
no output from the board. Bypassed the Dolby board and amplifier working. at this time i should have checked AM,FM and phono but was concerned about the Dolby board. Removed the Dolby board and repined and recapped
the Dolby board signal now passing through the Dolby board and Amp working. (once again did not check tuner) Rebuilt F2656 power supply replaced all caps and fuse resistors. Rebuilt F2544 tone board and cleaned pot's and switch's.
Rebuilt F2657 relay board. once again did not check tuner i think i went brain dead on that board so what did i do i rebuilt the F2549 and 2619 boards on the rf power supply installed 125c caps and resistors on to the chassis using thermal glue did not want to drill holes into the chassis . removed all the output transistors and they all tested good cleaned off old compound and replaced the mica pads and applied new compound and am now stumped on the tuner issues. All of my experience is
with Marantz and this is my first Sansui and learning as i go. i am posting some photos of my work. Thanks in advance for your Help.
i
I got the unit from my next door neighbor it's was in his garage for over 30 years in the original box (box kind of beat up but original none the less).
Connected to DBT and would not come out of protection mode F-2624 Driver Board and found 4 fuse resistors open. Replaced all fuse resistors and came out of protection mode and then rebuilt the board.
Rechecked the unit no output from either channel comming out of the F-2655 Dolby board only left channel signal going in to the board with no output. Traced right channel signal loss to broken trace on
the F2653 Eq/selector switch board repaired the broken trace with jumper wire. Rebuilt F2653 and checked and cleaned all wafers on the selector switch. now i have left and right signal going into Dolby board with
no output from the board. Bypassed the Dolby board and amplifier working. at this time i should have checked AM,FM and phono but was concerned about the Dolby board. Removed the Dolby board and repined and recapped
the Dolby board signal now passing through the Dolby board and Amp working. (once again did not check tuner) Rebuilt F2656 power supply replaced all caps and fuse resistors. Rebuilt F2544 tone board and cleaned pot's and switch's.
Rebuilt F2657 relay board. once again did not check tuner i think i went brain dead on that board so what did i do i rebuilt the F2549 and 2619 boards on the rf power supply installed 125c caps and resistors on to the chassis using thermal glue did not want to drill holes into the chassis . removed all the output transistors and they all tested good cleaned off old compound and replaced the mica pads and applied new compound and am now stumped on the tuner issues. All of my experience is
with Marantz and this is my first Sansui and learning as i go. i am posting some photos of my work. Thanks in advance for your Help.
i
The voltages are on the schematic. The output should be 12.5 VDC measured at pin 1.
You gave me the history but didn't answer the basic questions. What are the voltages on the tuner power supply pins 1 and 3. Please confirm you have no AM at all. You have FM but no stereo light. When you listen to a Stereo FM station, are you hearing stereo or mono?
- Pete
Vinnie Stu
New Member
Should be 12.5V. There is a trimmer pot on that board. See if you can adjust it down. Pin 2 should be 5.8V. It should decrease when you adjust the pin 1 voltage. Do you have an antenna connected? If not, don't expect FM stereo. Do the signal strength and centering meters work normally?
Don't know what to tell you for the lack of AM other than be sure the mode selector switch is clean. AM is controlled by an IC HA-1197. The schematic provides voltages at the various pins. That's where I would start but get the power supply voltage correct first.
- Pete
Don't know what to tell you for the lack of AM other than be sure the mode selector switch is clean. AM is controlled by an IC HA-1197. The schematic provides voltages at the various pins. That's where I would start but get the power supply voltage correct first.
- Pete
Vinnie Stu
New Member
outside antenna connected..signal meter@ 4...tuning meter centered ....trimmer will not adjust...found R05 12k resistor open i will order one and a new 10k pot, when i install them i will update thanks again pete
Vinnie Stu
New Member
So i replaced R05 resistor and trimmer pot. adjusted voltage @ pin 1 to 12.5v pin 2 stayed @ 8.5v . no change FM light inop no stereo and no AM. Did some digging and found pin 9 on f-2653 has no voltage that feed seems to be coming from pin 15 on f-2656 i can not seem to find why there is no voltage there..thanks pete
Looks like the regulated power supply TR03/TR04 on F2656 has failed. That supply is for the tone board F2544 (via the mic amp) and also the flat amp F2653 but the drawing does not reveal how it actually gets to that one.
Note that HA1197 has an absolute max voltage rating of 15V. It would not like 20V.
Vinnie Stu
New Member
thank you Doug i will look into that tonight i have been having trouble following the block diagrams this info is very helpful. ty
Vinnie Stu
New Member
Doug do you have replacement part # for those transistors ty
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Vinnie Stu
New Member
Hello Pete unfortunately i have not. i looked into tr03 and tr04 transistors on the power supply and there is no tr03 on the power supply it shows one in the schematics. i have 8v to the stereo and indicator bulbs so i believe they are not getting grounded. i still have no AM at all. just to throw a dart i replaced HA1196 and HA1197 with no luck. i was starting to look into power from f-2619 to f-2653 and see if it is going into and comming out of the selector switch. on one side it seems to be a ground problem on the other side it seems to be a power problem possible transistor on f-2549. i am at a total loss. that is why i did not post any updates
Keep the removed parts - they may not be faulty.
What power supply? The tuner power supply F-2619 only has three transistors, TR01, 02 and 03.
The voltage supply for the stereo light comes directly from the lighting circuit fuse F03 on the main power supply board. That supply is listed as 6.5V AC. The AC voltage is rectified by Diode D01 on F-2619. Since you are measuring 8v there, check the AC voltage at F03. You may also want to replace D01.
It looks like power is fed to the tuner board in two places. It goes from F-2619 pin 1 (C) to F-2653 pin 17 (C). It comes off F-2653 through pin (K) unswitched and pin (L) through D601. There are no pin numbers associated with these connections on board F-2653. From F-2653 (K) to the tuner board F-2549 pin 18 (K) and F-2653 (L) to F-2549 pin 31 (L).
You should have 12.5 DC volts at Pin 1 of F-2619. You should see nearly that same voltage at Pin 17 of F-2653. Then check to see if you have that same voltage at pin 18 on F-2649. Next check to see a lower DC voltage at pin 31 on the tuner board. That voltage is switched by the function switch so it will only be there when selecting AM or FM.
Let me know what you find.
- Pete
Vinnie Stu
New Member
will check over the weekend thanks
Vinnie Stu
New Member
f-2656 power supply has 3 transistors and the schematics show it has 4 transistors. thanks
Not unusual for Sansui schematics to be different than the actual board. Keep in mind you have two issues, No AM and No Stereo light. They are not related. The circuit detail I gave above is to confirm the power supply for the tuner board. This should shed some light on the No AM problem. The FM light will only work if your FM tuner is receiving and decoding FM stereo. Tune it to a strong FM station and listen for the difference in stereo right and stereo left. If you can't detect a difference in the sound between the two channels, you won't get a stereo light. If you can hear the difference between the two channels but the light is not on, check/replace R63 and TR09 on the tuner board.
- Pete
- Pete
