Marantz 2325 project

[sanjib]

SOLVED!!! Now time to move on to amp boards!!

 

[Steven Tate]

SOLVED!!! Now time to move on to amp boards!!

Well....don’t keep us in suspense!

 

[sanjib]

Well....don’t keep us in suspense!

A microscopic bit of solder made pin 2 connected to ground pad!!!

 

[Steven Tate]

A microscopic bit of solder made pin 2 connected to ground pad!!!

Nice hunting!

 

[sanjib]

After little hiccups and one weird thing, it is done, sounds awesome. I am going to post the details for each board in each post.

 

[sanjib]

Power supply board P-800

R801 150Ώ/5W - TT Electronics 150Ώ/7W Mouser 756-W22-150RJI
R804 10Ώ/0.5W - NTE 10Ώ/1W (I forgot to order this one from mouser!)
C803 470µF/63V - Nichicon PW 1200µF/63V Mouser 647-UPW1J122MHD
C804 220µF/63V - Nichicon PW 680µF/63V Mouser 647-UPW1J681MHD
C805 470µF/16V - Nichicon PW 470µF/35V Mouser 647-UPW1V471MPD
C806 220µF/63V - Nichicon PW 680µF/63V Mouser 647-UPW1J681MHD
C807 330µF/50V - Nichicon PW 330µF/50V Mouser 647-UPW1H331MPD
C808 0.047µF/50V - Wima MKS 0.047/µF/63V Mouser 505-MKS2C024701A00KA
C809 10µF/50V - Nichicon PW 22µF/50V Mouser 647-UPW1H220MDD
C810 0.01µF/50V - Wima MKS 0.01µF/63V Mouser 505-MKS2C021001A00MI
C811 10µF/16V - Nichicon PW 22µF/63V Mouser 647-1J220MED1TD
C812 47µF/16V - Nichicon PW 47µF/25V Mouser 647-UPW1E470MDD
C813 220µF/10V - Nichicon PW 220µF/35V Mouser 647-UPW1V221MPD6
H801/802 2SD331 - ON Semi MJE15032G Mouser 863-MJE15032G
H803 -2sc734 Mouser 512-KSC2383YTA
H804 -2sc945 Mouser 512-KSC2383YTA
H805 -2sc945 Mouser 512-KSC2383YTA
H806 -2sc1318 Mouser 512-KSC2383YTA
H807 -2sc1318 Mouser 512-KSC2383YTA
H808 -DS-131B Mouser 863-MUR1620CTG
H809 -DS-131B Mouser 863-MUR1620CTG
H810 -WZ-140 Mouser 512-1N5244B
H811 -WZ-071 Mouser 512-1N5236B
H812 -1S2471 Mouser 512-1N4148

 

[sanjib]

Pre-amp boar PE01
CE01/02 680pF - TDK 680pF/250V C0G Mouser 810-FG28C0G2E681JNT6
CE05/06 1µF/250V - Wima 1µF/250VDC Mouser 505-MKP4F041005DKSP1
CE09/10 100µF/10V - Nichicon PW 100µF/10V Mouser 647-UPW1A101MDD
CE11/12 10µF/35V - Nichicon ES bipolar 10µF/35V Mouser 647-UES1V100MEM
CE13/14 3.3µF/35V - WIMA film 3.3µF/50V Mouser 505-MKS23.3/50/10
CE33/34 1µF/25V - WIMA film 1µF/50V Mouser 505-MKS2B041001C00KS
CE35/36 3.3µF/25V - WIMA film 3.3µF/50V Mouser 505-MKS23.3/50/10
CE37/38 4.7µF/16V - WIMA film 4.7µF/50V Mouser 505-MKS2-4.7/50/10
CE39 35v/220uf -Elna 470µF/35V Elna 555-RFS35V471MJ7#5
HE03 2sc1327 - Mouser 512-KSC1845FTA
HE04 2sa721 -Mouser 512-KSA992FBU
HE05 2sc1327 -Mouser 512-KSC1845FTA
HE06 2sa721 -Mouser 512-KSA992FBU

 

[sanjib]

Now the main amp board P700. Here I initially did a mistake in one channel and a weird thing happened after that. In one channel I put PNP at H708 and NPN at H709 and tried to set up bias current and could not set it up. I have tried a few times! after discovering the mistake I replace those H708 and H709 with MJE15030G and MJE15031G and I found the R740 trimmer is extremely sensitive. Fully counter-clockwise reads 0mV and a little touch bring it to 30mV and nothing in between. So I replaced H714 and H715 with MJE243G and nothing changed. then I put old original transistors in place of H708 and H709 and I can set the bias smoothly. Next, I again put MJE15030/31 and replaced the trimmer with new bourn single turn 1kohms and the same problem persist, a little touch goes to 25mV but with this one, after just randomly touching (not rotating at all) the pot with a screwdriver I was able to bring it to 14.5 mV! I decided to try a 25 turn trimmer and after installing it I can smoothly set the bias current at 15mV!! I yet not understand with the almost same components in both channels why one is so sensitive to one turn trimmer pot!! Does anyone have any idea why is this happening?

Here is what have done in P700

C701 250V/1uf - Wima 1µF/250V 505-MKP4F041005DKSP1
C703 6.3v/33uf - Nichicon ES bipolar 33uF/25V Mouser 647-UES1E330MPM
C706 25v/10uf 555-RFS25V100ME3#5
C707 25v/10uf 555-RFS25V100ME3#5
C708/709/714/721 250V/0.1uF 505-MKS4F031003C00MS
C710/713 100pF - Vishay C0G 100pF/1KV Mouser 75-561R10TCCT10
C719/20 250V/0.033uF Wima 0.033uf/250V 505-MKP4F023303C00JS
H701 2sa722 512-KSA992FBU
H702 2sa722 512-KSA992FBU
H703 2sa722 512-KSA992FBU
H704 2sa720 512-KSA1013YBU
H705 2sc1318 512-KSC2383YTA
H708 2sc1669 863-MJE15032G (other channel 15030G)
H709 2sa839 863-MJE15033G ( other channel 15031G)
H710 2sc945 -Mouser 512-KSC945CYTA
H711 2sa733 KSA733CGBU (Now is non-stock in mouser)
H712 2sa733 KSA733CGBU
H713 2sc945 Mouser 512-KSC945CYTA
H714 2sc496 863-MJE243G
H715 2sc496 863-MJE243G
H718 VD1122 512-1N4148
H719 VD1122 512-1N4148
H720 1S2471 512-1N4148
H721 1S2471 512-1N4148
R719 1.2K/2W 660-MO2C122J
R720 1.2K/2W 660-MO2C122J
R741 47/1W 660-MO1C470J
R742 47/1W 660-MO1C470J
R746 22/3W 660-MOS3CT631R220J
R747 2.2/2W 660-MOSX2CT52R2R2J

 

[Steven Tate]

Whether to replace transistors or not is kind of a philosophy thing. I have found that very often, when you change a working transistor to a modern equivalent, you somewhat alter your ability to set bias and/or offset. If you change large numbers of transistors, you can be multiplying the changes. I have done what you did: change a semi, find I have trouble setting bias, put the old one back in, and bias sets normally. As a result, my philosophy is to leave semiconductors alone unless they test bad, or are known troublemakers like 2SC458’s, VD1212’s, etc. I’m not saying this is best practice. It’s just the philosophy I have settled on at this point. Great job on that 2325. When you get one of those working right, you have something special.

 

[sanjib]

Phono board P400

C401/402 1µF/25V - WIMA film 1µF/50V Mouser 505-MKS2B041001C00KS
C403/404 47µF/16V - Nichicon ES 47µF/16V Mouser 647-UES1C470MPM1TD
C413 100µF/35V - Vishay axial lead HE 220µF/100V Mouser 594-2222-120-19221
C414/415 1µF/250V - Wima 1µF/250V 505-MKP4F041005DKSP1
H401 2sc1344 512-KSC1845FTA
H402 2sc1344 512-KSC1845FTA
H403 2sc1344 512-KSC1845FTA
H404 2sc1344 512-KSC1845FTA
H405 2sc458 512-KSC1845FTA
H406 2sc458 512-KSC1845FTA
H407 1s2473 512-1N4148
H408 1s2473 512-1N4148
H409 VD1212 512-1N4148 (x2 in series)

Buffer amp PH-01

CH05/06/07/ 4.7µF/35V - WIMA film 4.7µF/50V Mouser 505-MKS2-4.7/50/10
CH13 220µF/35V - Nichicon KL 220µF/35V Mouser 647-UKL1V221KPD
CAREFUL! The silkscreen is wrong on CH13. Negative should face the edge of the board

HH01/02/03/04 2SC1345 - Fairchild KSC1845 Mouser 512-KSC1845FTA
HH09/10 2SC1318 - Fairchild KSC2383YTA Mouser 512-KSC2383YTA

PL01 Dolby, Tone & Meter Circuit Board

CL05/06/07 10µF/16V - Nichicon KL 10µF/16V Mouser 647 UKL1C100KDD1TD
10/11/12/13
CL/14 33µF/35V - Elna Silmic II 33µF/50V Mouser 555-AFS50V330MH4#5
(Bottom of Board)

 

[sanjib]

Cosmetics
All indicator, dial, and meter lamps are replaced and also the melted light housing. It is hooked up with fully restored Polk SDA-1C and sounding amazing!

 

[sanjib]

Thank you for all the suggestions and help!!!

 

[sanjib]

When I was checking the phono input I notice a slight hum when volume knob in 11 o clock position regardless the turntable is connected or not. This is only for phono all other inputs are fine.

 

[Steven Tate]

Bottom is on....correct? They will nearly always hum if the bottom is off. It partially shields the Phono amp from 60 Hz interference. 11 o’clock is pretty high, and Phono amps are very sensitive. I’m not sure most of them wouldn’t have slight hum at that level with no signal. Hopefully others will have an opinion on that.

 

[sanjib]

Bottom is on....correct? They will nearly always hum if the bottom is off. It partially shields the Phono amp from 60 Hz interference. 11 o’clock is pretty high, and Phono amps are very sensitive. I’m not sure most of them wouldn’t have slight hum at that level with no signal. Hopefully others will have an opinion on that.

Steven: Everything is alright now. Actually it was not humming simply like air blowing faintly and I guess it is pretty normal at high volume in particular for phono. Thank you!