• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

marantz 4400 Power board p800

S

sebtus

New Member
Hi all.
It got not working marantz 4400 with a blown cap on p800 board. i have replaced all caps and here comes the problem. (H809 was bad as well. i got that replaced.)
I measured the voltages across the board and all i got was AC voltage. I dont have any DC anywhere on the PCB. I checked all rectifying diodes (out of the circuit) and nothing abnormal was noticed. all transistors checked good. i was thinking to replace all diodes just to be sure, but i cant find the replacements. Does anybody have P/N to replace H801-H806 diodes, or maybe you have an idea what else could cause this problem.

Thank you

index.php
 
Register to hide this ad
All the JP's and J801 through J809 are AC. J813 has the DC voltages, pin 10 is regulated +35VDC, pin 11 is regulated +13VDC, you can trace out the rest.
If there really is AC everywhere, look for an open ground or a broken wire somewhere.

Tom
 
Thank you for your respond.

i have measured all JP voltages:
JP01 - 43VAC
jP02 - 38VAC
jP02 - 344VAC
jP04- 37VAC
JP05 -176VAC
jP06- 108VAC
jP07 -15.5VAC
jP08 -70VAC

which i think is correct. However J813 connector i have the following measurements:
J813
Pin 1 - 43VAC - OK
2- 38VAC- OK
3-38VAC
4-38VAC
5-38VAC
6-38VAC
7-38VAC
8-38VAC
9-38VAC
10-38VAC
11- 34VAC
which is not OK as you can see.
when i take all measurements P800 board has only PP01 BOARD plugged in, i disconnected j813 connector due the fact i don't have correct voltages there and i don't want to damaged something down the line with ac voltages.
I cant find dc anywhere on the board...... very confused

Any help greatly appreciated.
 
Last edited:
You say you have different voltages on jp01 and jp02, but that looks like it across the fuse pp01. Unless i'm missing something they should be the same. Not your problem, but try checking polarity across your diodes.
Any complete winding going to two opposing diodes should turn to dc after the diodes. For example, 801/803 should be dc.
JP05 looks like a sort of ground leg, after it gets past j804/805. Maybe use that for a reference to check your diodes.
 
i would take all fuses out and give them a good clean and test them . then test all AC inputs with fuses out .
 
I mistyped the markings.
JP02 - 43VAC
jP03 - 38VAC
jP04 - 344VAC
jP05- 37VAC
JP06 -176VAC
jP07- 108VAC
jP08-15.5VAC
jP08-70VAC
Sorry
 
Normally the chassis is what you would use for a reference but with J813 disconnected, there is no connection from the circuitry to the chassis. Use J812 as the reference for your meter and see if you have DC voltages now.

Tom
 
Sir, Tom you are the man...
Yes after looking at the board and your tip i have came to conclusion that te power supply works. Chassis was not a good ground. I used J812 like you sad and Boom all works. Voltages seem to be right on.
Thank you very much. I guess your "Marantz Specialist" note under your name is not just for show heheheh :) i guess i should make mine Marantz Newbie.

Well i figure i give you guys a quick story on this Marantz 4400.
It is a restoration project, The unit was found by my brother in law at the NYC construction dumpster. It is in a bad shape. When i got it nothing was working. Now power.
After a brief inspection i noticed that some butcher was working on it before. My findings so far:
blown fusses, Fusses with wrong values, Power supply looked like a mouse nest, Power supply with blown caps, Airplane toggle switch as a power switch. Dust, dirt and rust on the chassis.

I started with rebuilding the power supply, I replaced all the caps except the 2 ceramic ones. Then i checked all diodes (Huntron tracker 2000 - works great for that purpose) and i found H809 zener diode short. i did not have 14v handy so for test purposes i installed a 12v i had available.
Then the Ac issue which you guys helped me with was resolved.

Dial lights and mode selector lights came up so there is a sign of life :)

Now the new issue that came up: when i plug J033 to J813 i get an arc between pin 2 and 3. i already desoldered the J813 to look for short/arc burns anywhere but all looked OK. I will have to investigate some more.

That's where im am at this point.

Here you have a few pictures.


 
Update:
i have cleaned J813 and gave it a shot.. and.... no arcing. speaker relays engaged. scope blinked.
i got speakers hooked up. tuned in to a random radio station and Katy Perry - Roar came up.... scratchy / and not close to be a clean audio but very satisfying at this point.



 
That's quite a unit to find tossed out. Very cool that the scope tube is good! Nice work so far.
 
I believe pin 2 on J813 feeds 200V to the scope circuitry, so an 'arc' when plugging/unplugging that jack may be normal.
If you found blown caps on the power supply there are probably more elsewhere.
:thumbsup: on your efforts so far!

Tom
 
Thank you.
i will try to get all the electrolytic caps ordered once i make my long parts list and get them all replaced. it's going to be a project. i start with cleaning all pots and switches. i will keep your posted.
BTW where can i get a good power switch for this unit. the toggle switch does not work for me lol.


side note. i see that some of you have bunch of audio equipment listed in your signatures. is that what you own? or is it a wish list.
Im new here and i want to sure i fit in well. :)
 
I know that if you leave the scope supply unplugged, the caps will hold their charge quite awhile. Guess how I found out? :yikes:

For the power switch on most Marantz units here's one from Mouser: 612-P227EE2B20B. They were out of stock last time I checked. Also from DigiKey is EG1018. Warning! I didn't go look in my 4400 to see if it's the weird switch with extra contacts.

The signatures are usually what folks have on hand or their systems. Mine has to do with my 4 legged mono woofer!!
 
That would make sense, because j812 is the same as j804, just the other end that grounds the transformer off center.Its odd they didn't ground it on the transformer end.:idea:
Nice Find and not all bent up. Good job so far. :thumbsup:
 
Last edited:
rBuckner said:
For the power switch on most Marantz units here's one from Mouser: 612-P227EE2B20B. They were out of stock last time I checked.
Click to expand...

Mouser just shipped my backorder on those switches. I ordered them back in February!
 
Here is something i stole from Echowars, with his blessing, i hope. There is also another approach (Triac) that he had for bypassing the current. I'll see if i can find that thread, John

EchoWars Freddie Get Ready - Rock Steady Subscriber
Messages:
27,702
Location:
Kansas City
Fig. 1. You just have to determine what the screw spacing is.

The E-Switch has two sides, each rated for 7A. Parallel them for a 14A rating.

You'll also need a new saftey cap. The Kemet 10,000pf will work well. Part #399-9537-1-ND.

Digikey numbers all.

Attached Files:
 
You must log in or register to reply here.
Back
Top Bottom