• 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

Need 2600 Schematic... Anyone know where I can find one?

jeffsplat88

jeffsplat88

Member
Hi Folks
I just picked up a 2600 that is not running. I need to find a schematic for it so I can start measuring the transformer. I can't find one on HiFi engine. Anyone got a link?
Thanks!
 
Register to hide this ad
Rick @ Stereomanuals.com has the best professionally done service manuals available.
I have purchased many from him and they are top notch.
He is one of the last outfits still providing this service.
He has the full 108 page service manual for the 2600 including large oversized schematics for around $28.

Bob
 
Thanks Guys!
I will for-sure absorb every word of the 2600 postings here.
I ended up getting the schematic from here: http://www.manualscenter.com/manuals/marantz/2600-service-manual.html#.W2Ew0NWpHDc
And it was very good quality on the schematics. Satisfied for the price. If anyone wants me to post or send it out, let me know.

I'll try to post my progress and results here to help contribute to the AK community (lord knows I'm an avid reader and it's time for me to contribute). Here's what I've got so far:

When I bought the unit, I brought up on Variac and the unit had no signs of life other than the fan coming on full speed. It appeared that the power soaking turn-on circuit and relay never clicked closed, and the 10 ohm power soaking resistor got hot and may have cooked.

I isolated the transformer secondaries by removing the power supply board and clipping secondaries to the two amplifier rectifiers. I brought up on variac and was able to measured 125vac on one of the amp secondaries. This is below the 140vac I should be reading. I measured the 10 ohm power soaking resistor and got 82 ohms across it so it must be damaged and high-Z. I shorted that out with a jumper then re powered up the transformer and got the spec 140 vac on the secondary. At this point, this is a relief in that it looks like the transformer is good.

This would then lead to a theory that one or more of the main caps are shorted and/or one or more of the main diodes are shorted causing high load on the transformer and keeping the relay from closing and causing high current through the 10 ohm resistor.

Up next:
  • Measure the other 140vac secondary
    Measure all the other secondaries
  • Measure the main caps
  • Measure the main diodes.
 
If the soft start resistor is fried - easy to check, i'd be heading towards shorted outputs rather than main caps- main caps rarely go bad.
 
Hi All, Today's update:
Tested the main power amp rectifiers and found the “right” side rectifier had a shorted diode. GOOD! Easy fix. Testing the main caps now:
  • Cap #1 Pos: less than 150uA leakage at 60 volts after 1Hr. This is respectable for the age.
  • Cap #1 Neg: (Has a 4.7K in parallel so need to see stable at less than 12.7ma). Stabilized at 12.95mA at 60 volts after 1Hr. Close enough within resistor tolerance so I'm confident that side of the cab is good and not leaking.
Up next (wont get to it until this weekend) is to test cap #2. After that I'll replace the bridges, the start-up resistor and then bring up the amps with light-bulbs in series with the primaries to check for bad outputs. But right now, there is certainly a smoking gun with the bad bridge rectifier. They look small for the amount of power they have to sustain. I'm hopeful that everything will come up normally with those replaced with some beefier units.
 
I'm hoping for you that the output transistors are all good. It's a bit of a chore pulling the heatsink / amp tunnel assembly. If you do it's worth replacing the fan with a nice new ball bearing model that 'Catrafter' was kind enough to inform me about. I don't have my parts file but I think it's this one:

Mouser part number: 5912-4606Z
 
You must log in or register to reply here.
Back
Top Bottom