Leestereo's Restoration and Upgrade Of A Marantz 2270

I have two units of them, i wil recap them. So this thread is the most important to me at this moment.
Does anyone knows if the recap process -or caps values- should be different in elder model?
One of my 2270's is older that the other, the older model has 5 fuse inside, beside the right channel amplifier.
 
The one with the fuses inside would be a very early production model. There are several variations in the 2270. As far as I know, the major variations are in the amp boards. You can find all the service manuals on HifiEngine and possibly here on AK. They will show the differences in the schematics, based on serial number. The easiest approach is just to replace the caps with the same value because Marantz made lots of on-the-fly production modifications. If you replace what's there, you are safe. For certain of the capacitors, you can increase size. Notably these are in local PSU filtering and a couple other spots. But it's safest to replace in kind. If you start a conversation, I can send a list of the capacitors that indicates replacement values along with some other notes that might be helpful - gleaned from the experts here on AK. There are lots of threads on AK that give information about the 2270.

In addition to recapping, you should replace the SC458 transistors on the phono PCB and the VD1122 diodes on the phono board. There are also several variations of the toneboard but they are similar.

Hope this helps a bit.
 
I am recapping a 2270 using this awesome thread and so far I've done the power supply board and the amplifier boards. Of course I've replaced the main caps. I need to get it working at this point and afterward I will complete the recapping. The thing is that when I push the power button, the front lights up for just a split second and the fuse blows. Then the STEREO indicator light glows for about a second. I've checked all of my work and can't find anything wrong. Any suggestions as to what to check next?
 
Are you sure about the polarity of connections on your big caps? Negative of one should connect to positive of the other via the grounding bar, leaving a negative for the white power wires and a positive for the red power wires.
 
Yes I have both mounted the same way with their negative poles closest to the rear of the unit. I also used the star ground method used by the OP. Thanks for your input! I'm just at a loss at this point.
 
Nice work on the ground strap. But what are those bypass capacitors doing in there...(just kidding, not trying to start a religious argument).
 
I know this looks a little rough but it was rough when I got it. I'm thinking the board needs replacement. I've checked many times to be sure all the new caps are in correctly. If not the board then maybe the transformer went out inexplicably. The fuse blows within a split second after power-up. I cannot find the smoking gun amongst the things I've done. When I got it I was able to get the receiver going by fingering the old relay which I have replaced with an OMRON MY2 (Digikey part# Z182). I'm desperate here and any insight would be GREATLY appreciated.
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Did you remove the output transistors when doing your work? Any chance their legs or connectors are touching the heat sink or that they were reversed? Whether you did or didn’t, I would remove the outputs on that amp and Check with DBT to see if the outputs were shorted in the process.
 
I can't see how I could have shorted the outputs because they can only go in one way. So yes, I did have them out while I was working on the power amp boards. While I was at it I replaced the decoupling caps with 1uF 250V polyester film caps, non-polar. I don't suspect that the originals were defective so I could put those back but I'd rather not have to dismantle the heat sinks, etc. unless it's necessary.

Would it be okay to turn the unit on with the outputs removed just to see if it will come on without the fuse blowing? Would it even make sense to try such a thing?
 
Is that a solder bridge I see from the relay coil trace to the trace with the blue wire?

Tom
Are you concerned that the 2 traces leading to the relay terminals on the left are bridged? I just looked at the board and didn't see that, if that's what you're asking. I don't see any solder bridges on that board.
 
I can't see how I could have shorted the outputs because they can only go in one way. So yes, I did have them out while I was working on the power amp boards. While I was at it I replaced the decoupling caps with 1uF 250V polyester film caps, non-polar. I don't suspect that the originals were defective so I could put those back but I'd rather not have to dismantle the heat sinks, etc. unless it's necessary.

Would it be okay to turn the unit on with the outputs removed just to see if it will come on without the fuse blowing? Would it even make sense to try such a thing?
A better way to test the unit is with a dim bulb tester. Turning it on to see if a fuse blows is just asking for more damage. You can remove the outputs and fire it up with a dim bulb tester attached and see if the bulb continues to glow brightly or if it dims after a few seconds. Of course, you need to protect the leads that attach to the output terminals to be sure they don't short against something. A dim bulb tester will indicate the presence of a short while giving some protection against large current flow that would damage other components. If you are going to work on vintage gear, a DBT is pretty much a must.
 
Do you have a part number for the 1uF WIMA? on the tone board?
Need to be sure they have the long leads to stretch over to C411.
Love this thread btw.
 
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