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2250 Rebuild-Distortion in the first 10 seconds - then fine

Paul Malloy

Paul Malloy

Active Member
Just finished rebuilding my Marantz 2250, and everything seems fine except that in the first 10 seconds of powering up, the sound gets distorted, then it's fine. At first, I thought it was just some dirty pots since it only happens when I power up and I'm increasing the sound from zero volume up, but I cleaned them three times and still there. I also tested and replaced HE03 thru HE05 twice.

Seems to be in the Pre Amp section, since it doesn't happened when I put sound through the Main In RCA cable via my bluetooth.

Here's a video:
https://drive.google.com/file/d/1omdgPZB_Lql-gjOt9--wrUox8Lw3S8Y6/view?usp=sharing

Here's list of parts I replaced:

Main Caps/Aluminum Electrolytic Capacitors - Radial Leaded 10000uF 63 Volts 20% Tol. (40mm dia. not 35mm)(LKG1J103MKN)
Bypass Caps/Film Capacitors 250VDC 2.2uF 10% MPET L/S=22.5mm

FM Front End (P100)
OK-Leave

AM Tuner (P150)
C167 - Originally 22uF 16v / Installed 22uF 50v (UPW1H220MDD)
C168 - Originally 100uF 16v / Installed 100uF 35v (UPW1V101MPD)
C169 - Originally 4.7uF 35v / Installed 4.7uF 50v (UPW1H4R7MDD)
C170 - Originally 100uF 16v / Installed 100uF 35v (UPW1V101MPD)
C171 - Originally 1uF 50v / Installed 1uF 63v (MKS2C041001F00JA)
C172 - Originally 100uF 16v / Installed 100uF 35v (UPW1V101MPD)
C173 - Originally 4.7uF 35v / Installed 4.7uF 50v (UPW1H4R7MDD)

FM IF AMP (P200)
C237- Originally 10uF 16v / Installed 10uF 50v (UPM1H100MDD)
C240- Originally 100uF 16v / Installed 100uF 35v (UPW1V101MPD)
C242- Originally 100uF 16v / Installed 100uF 35v (UPW1V101MPD)
C244- Originally 10uF 16v / Installed 10uF 50v (UPM1H100MDD)
C245- Originally 10uF 16v / Installed 10uF 50v (UPM1H100MDD)
C246- Originally 10uF 16v / Installed 10uF 50v (UPM1H100MDD)

MPX Stereo (P300)
C302 - Originally 33uF 10v / Installed 33uF 35v (EEU-FM1V330)
C304 - Originally 22uF 16v / Installed 22uF 50v (UPW1H220MDD)
C306 - Originally 22uF 16v / Installed 22uF 50v (UPW1H220MDD)
C307 - Originally .47uF 50v / Installed .47uF 100v (MKS2D034701E00JI00)
C308 - Originally .22uF 50v / Installed .22uF 63v (MKS2C032201B00JA00)
C309 - Originally .22uF 50v / Installed .22uF 63v (MKS2C032201B00JA00)
C323 - Originally .22uF 35v / Installed .22uF 63v (MKS2C032201B00JA00)
C324 - Originally .22uF 35v / Installed .22uF 63v (MKS2C032201B00JA00)
C325 - Originally 1uF 35v / Installed 1uF 63v (MKS2C041001F00JA)
C326 - Originally 1uF 35v / Installed 1uF 63v (MKS2C041001F00JA)
C327 - Originally 220uF 25v / Installed 220uf 35v (UKT1V221MPD)
C328 - Originally 220uF 16v / Installed 220uf 35v (UKT1V221MPD)
C329 - Originally 10uF 16v / Installed 10uF 50v (UPM1H100MDD)
C331 - Originally 1uF 50v / Installed 1uF 63v (MKS2C041001F00JA)
C332 - Originally 10uF 16v / Installed 10uF 50v (UPM1H100MDD)
C337 - Originally 4.7uF 35v / Installed 4.7uF 50v (UPW1H4R7MDD)
C338 - Originally 1uF 50v / Installed 1uF 63v (MKS2C041001F00JA)
C342 - Originally 10uF 16v / Installed 10uF 50v (UPM1H100MDD)

Phono AMP (P400)
C401 - Originally 1uF 25v / Installed 1.0uF 63v (MKS2C041001F00JC00)
C402 - Originally 1uF 25v / Installed 1.0uF 63v (MKS2C041001F00JC00)
C403 - Originally 47uF 16v / Installed 47uF 35v (UKL1V470KPDANA)
C404 - Originally 47uF 16v / Installed 47uF 35v (UKL1V470KPDANA)
C413 - Originally 100uF 35v / Installed 100uF 50v (UKA1H101MPD1)
C414 - Originally 1uF 250v/ Installed 1uF 100v (MKP4D041005D00JSSD)
C415 - Originally 1uF 250v / Installed 1uF 100v (MKP4D041005D00JSSD)
H401 - Originally 2SC1344 / Installed KSC1845FTA
H402 - Originally 2SC1344 / Installed KSC1845FTA
H403 - Originally 2SC1344 / Installed KSC1845FTA
H404 - Originally 2SC1344 / Installed KSC1845FTA
H405 - Originally 2SC458L / Installed KSC1845FTA
H406 - Originally 2SC458L / Installed KSC1845FTA
H407 - Originally 1S-2473C / Installed 1N4148
H408 - Originally 1S-2473C / Installed 1N4148
H409 - Originally VD1212 / Installed Dual 1N4148

Left / Right Amp Boards (P700) = QTY 2 Boards
C701- Originally 3.3uF 25v /Installed 3.3uF 63v (MKS2C043301K00KSSD)
C702- Originally 10uF 35v / Installed 10uF 35v (UKL1V100KDDANA)
C704- Original 47uF 50v / Installed 47uF 50v (UPW1H470MED) - Error in service manual 4.7uf should be 47uf
C705- Original 4.7uF 16v /Installed 4.7uF 50V (UPW1H470MED) - Error in service manual 4.7uf 10v should be 47uf 16v
C706- Original 220uF 50v / Installed 220uF 50v (UKA1H221MPD)
H702 - Original 2sa763/Installed KSA992FBU (Differential Pairs-H703)
H703 - Original 2sa763/Installed KSA992FBU (Differential Pairs-H702)
H704 - Original MV-13/Installed dual 1N4148
H710-Originally 2SC945/Installed KSC1845FTA (Differential Pairs-H711)
H711-Originally 2SA733/ Installed KSA992FBU (Differential Pairs-H710)
R732/R733-Orginally 0.2ohm 5W/Installed 0.2ohm 5W (LVR05R2000FE73)
H001 thru H004-Orginally SC21343/Installed MJ21194G
Flyback X 4 -UF4004-M3/54

Power Supply Board (P800)
C801 - Original 220uF 63v / Installed 220uF 63v (UPM1J221MHD6)
C802 - Original 100uF 50v / Installed 100uF 63v (UKW1J101MPD)
C804 - Original 22uF 35v / Installed 22uF 50v (UPW1H220MDD)
C805 - Original 330uF 50v / Installed 330uF 63v (UPM1J331MHD)
C806 - Original 470uF 16v / Installed 470uF 35v (UPW1V471MPD)
C807 - Original 4.7uF 50v / Installed 4.7uF 63v (UPW1J4R7MDD)
C808 - Original 47uF 16v / Installed 47uF 35v (UKT1V470MDD)
C809 - Original 220uF 10v / Installed 220uF 25v (UPW1E221MPD)
R807 - 150 ohm 5 watt /Installed 150 ohm 7 watt (W221500JRLF)
H801 - Original 2SD330 / Installed MJE15032G
H802 - Original 2SC1318 / Installed KSC2383YTA
H803 - Original 2SC945 / Installed KSC1845
H804 - Original 2SD331 / Installed MJE15032G
H805 - Original 2SC945 / Installed KSC1845
H806 - Original 2SC1318 / Installed KSC2383YTA
H807 - Original 2SC1318 / Installed KSC2383YTA
H808 - Original DS131B / Installed BYQ28E-200,127 (Dual Diode)
H809 - Original WZ-071 (Zener) / Installed 1N4737A (OnSemi)
H810 - Original WZ-140 (Zener) / Installed 1N4744A (OnSemi)
H811 - Original DS131B / Installed Dual Diode (BYQ28E-200,127)
H812 - Original 1S2471 / Installed 1N4148
Relay MY2Z-02-DC22 relay / Installed MY2-02-DC24

Tone AMP (PE01)
CE05 - Originally 1uF 250v / Installed 1uF 100v (MKP4D041005D00JSSD)
CE06 - Originally 1uF 250v / Installed 1uF 100v (MKP4D041005D00JSSD)
CE09 - Originally 100uF 10v -Removed with BA312 Kit
CE10 - Originally 100uF 10v -Removed with BA312 Kit
CE11 - Originally 10uF 35v -Removed with BA312 Kit
CE12 - Originally 10uF 35v -Removed with BA312 Kit
CE13 - Originally 3.3uF 35v -Removed with BA312 Kit
CE14 - Originally 3.3uF 35v -Removed with BA312 Kit
CE33 - Originally 1.0uF 25v / Installed 1.0uF 63v (MKS2C041001F00JC00)
CE34 - Originally 1.0uF 25v / Installed 1.0uF 63v (MKS2C041001F00JC00)
CE35 - Originally 3.3uF 35v / Installed 3.3uF 63v (MKS2C043301K00KSSD)
CE36 - Originally 3.3uF 35v / Installed 3.3uF 63v (MKS2C043301K00KSSD)
CE37 - Originally 4.7uF 16v / Installed 4.7uF 63v (MKS2C044701M00KO)
CE38 - Originally 4.7uF 16v / Installed 4.7uF 63v (MKS2C044701M00KO)
CE39 - Originally 220uF 35v / Installed 330uF 35v (UPW1V471MPD)
HE03 - Originally 2SC1327 / Installed KSC1845FTA
HE04 - Originally 2SA721 / Installed KSA992FBU
HE05 - Originally 2SC1327 / Installed KSC1845FTA
HE06 - Originally 2SA721 / Installed KSA992FBU
HE01/HE02-Sparko BA312-M kit

Dolby Amp (PC01)
CC01 - Originally 1uF 25v / Installed 1uF 63v (MKS2C041001F00JA)
CC02 - Originally 1uF 25v / Installed 1uF 63v (MKS2C041001F00JA)
CC03 - Originally 1uF 25v / Installed 1uF 63v (MKS2C041001F00JA)
CC04 - Originally 1uF 25v / Installed 1uF 63v (MKS2C041001F00JA)
 
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Check your solder joints in the tone and pre-amp boards. Sure sounds like something goofy when cold that makes better contact when it warms up.

This is where an oscilloscope is invaluable -- it lets you see where the distortion is .

If it's both channels its a power supply issue - -don't forget that the tone, phono, and pre-amp section have lower voltage power supplies separate from the main amp.

And always suspect zener diodes involved in power supply regulation for improper operation.....
 
I'm thinking this sounds like bad differential pair transistors. Have they been replaced? From Echowars comments in an old AK thread (on model 2270):
"Commonly, the input pairs (751,752) need replacing. They are called a differential pair, and perform an important function. For some reason, a lot of Marantz receivers have issues with these transistors and they need to be replaced. The new ones need to be matched in pairs for replacement. I use Zetex ZTX795A's. If you went this way, the Zetex ZTX795A's are CBE layout instead of the 2SA640's BCE layout, and you won't be able to heatshrink them together like the originals are (which means offset might drift during warmup a little more than the stock transistors, but is not really a big deal)."
 
Last edited:
dankik said:
Did you really increase this capacitance on the Tone Amp, or is it a typo?
Click to expand...
Not a typo (part number was a typo), but I meant to replace it with a 220uF cap. I installed a 330uF right now to CE39 - Installed 220uF 50v (EEU-FM1H221).Distortion is still there.

Good eye! I thought I caught all those.

Paul
 
Last edited:
blhagstrom said:
With all that rework, I would look for trace damage. A cracked trace next to a solder pad.
Good eyes and good light.
Click to expand...

Plan on doing that first. I think a good magnifying glass is also needed. I miss too much with just my eyes.

Too busy with other chores this weekend to get back to the receiver.

Thanks-

Paul
 
LWB said:
I'm thinking this sounds like bad differential pair transistors. Have they been replaced? From Echowars comments in an old AK thread:
"Commonly, the input pairs (751,752) need replacing. They are called a differential pair, and perform an important function. For some reason, a lot of Marantz receivers have issues with these transistors and they need to be replaced. The new ones need to be matched in pairs for replacement. I use Zetex ZTX795A's. If you went this way, the Zetex ZTX795A's are CBE layout instead of the 2SA640's BCE layout, and you won't be able to heatshrink them together like the originals are (which means offset might drift during warmup a little more than the stock transistors, but is not really a big deal)."
Click to expand...

I think I replaced all the differential pairs everywhere on the boards. Will recheck service manual.

Thanks-

Paul
 
Just to double check, after replacing the caps you had adjusted the 35V, DC Offset, and Idle Current per service manual? And, you were able to adjust both channels OK?
 
Have you jumped the power switch? So that it will be on all the time and see if it still occurs?

You did not happen to spray anything into the power switch?
 
dankik said:
Just to double check, after replacing the caps you had adjusted the 35V, DC Offset, and Idle Current per service manual? And, you were able to adjust both channels OK?
Click to expand...

The audio adjustments were done several times over the rebuild, but not after changing the 330uF cap.

I will do that later today.

Paul
 
Please tell us about your differential pair transistors. They should be matched in HFE and shrink-wrapped together to match temperature.
 
LWB said:
Please tell us about your differential pair transistors. They should be matched in HFE and shrink-wrapped together to match temperature.
Click to expand...

None of the pairs were heat shrinked together because the boards are not setup to have the faces of the transistors match up. I did match the HFE of transistors that were in pairs that I replaced.

I think I changed all of the transistors in the unit that are known problems..
 
You wrote before that you have isolated the problem to the Pre-amp section. My advice you should look at your work on the BA312 kit installation section. Do you have a scope?
 
Unfortunately, I don't have a scope.

Maybe I should have said before the amp section since the problem is not there if I feed sound through the Main In RCA cable inputs via a bluetooth device. Here's a video:
https://drive.google.com/file/d/1omdgPZB_Lql-gjOt9--wrUox8Lw3S8Y6/view?usp=sharing

Sound distortion is in both sides, and somebody suggested that is more likely in the power supply. I plan to start on the P800 board and look for bad solder joints/trace damage.

Paul
 
Just a couple of quick questions: does the distortion occur on ALL inputs (AM, FM, Phono, Aux, Tape1, Tape2)? Do you hear it when listening with headphones?
 
Paul Malloy said:
Tone AMP (PE01)
CE05 - Originally 1uF 250v / Installed 1uF 100v (MKP4D041005D00JSSD)
CE06 - Originally 1uF 250v / Installed 1uF 100v (MKP4D041005D00JSSD)
CE09 - Originally 100uF 10v -Removed with BA312 Kit
CE10 - Originally 100uF 10v -Removed with BA312 Kit
CE11 - Originally 10uF 35v -Removed with BA312 Kit
CE12 - Originally 10uF 35v -Removed with BA312 Kit
CE13 - Originally 3.3uF 35v -Removed with BA312 Kit
CE14 - Originally 3.3uF 35v -Removed with BA312 Kit
CE33 - Originally 1.0uF 25v / Installed 1.0uF 63v (MKS2C041001F00JC00)
CE34 - Originally 1.0uF 25v / Installed 1.0uF 63v (MKS2C041001F00JC00)
CE35 - Originally 3.3uF 35v / Installed 3.3uF 63v (MKS2C043301K00KSSD)
CE36 - Originally 3.3uF 35v / Installed 3.3uF 63v (MKS2C043301K00KSSD)
CE37 - Originally 4.7uF 16v / Installed 4.7uF 63v (MKS2C044701M00KO)
CE38 - Originally 4.7uF 16v / Installed 4.7uF 63v (MKS2C044701M00KO)
CE39 - Originally 220uF 35v / Installed 330uF 35v (UPW1V471MPD)
HE03 - Originally 2SC1327 / Installed KSC1845FTA
HE04 - Originally 2SA721 / Installed KSA992FBU
HE05 - Originally 2SC1327 / Installed KSC1845FTA
HE06 - Originally 2SA721 / Installed KSA992FBU
HE01/HE02-Sparko BA312-M kit
Click to expand...
Your list above of what was removed and installed with the Sparkos kit doesn't match with their document instructions. Could you please verify the following:
1. REMOVE CAPACITORS CE07/08
2. REMOVE CAPACITORS CE09/10
3. REMOVE CAPACITORS CE11/12
4. REMOVE CAPACITORS CE14/13
5. REMOVE RESISTORS RE13/14
6. REMOVE RESISTORS RE11/12
7. REMOVE RESISTORS RE15/16
8. REMOVE RESISTORS RE17/18
9. REMOVE RESISTOR RE73 - THIS RESISTOR IS CALLED RE07 IN MARANTZ MODEL 2330.​
And please verify that these components have been installed:
1. INSTALL NEW BA312-M MODULES USING PIN#1 TO PIN#1 OF HE01/HE02 ON BOARD
2. INSTALL 47µF CAPACITORS AT CE09/10 LOCATION OF PE01 BOARD. BE SURE TO OBSERVE POLARITY AND INSTALL WITH THE CORRECT ORIENTATION.
3. INSTALL 10 µF CAPACITORS AT CE13/14 LOCATION OF PE01 BOARD BE SURE TO OBSERVE POLARITY AND INSTALL WITH THE CORRECT ORIENTATION.
4. INSTALL 22 OHM 1/2Watt RESISTOR AT RE73 OF PE01 BOARD. THIS RESISTOR IS CALLED RE07 IN MARANTZ MODEL 2330.
5. SOLDER NECESSARY CONNECTIONS & REINSTALL PE01 AND MOLEX CONNECTOR. REASSEMBLE UNIT.
​
 
Just got home from work and went to take a look at the receiver, hot water heater was leaking, basement has a 1/2" of water on the floor, so I need to go take care of this first.

Will update when I get back to it.

Thanks-

Paul

BTW-Always something with a 120 year old house.
 
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