Leestereo's Restoration and Upgrade Of A Marantz 2270

[beans]

NPN in a PNP hole or vise versa?

Tom

The only transistors I've replaced are the two H760's on the amp boards. The new ones are TO225AA which are NPN.

I have built a dim bulb tester and with a 60 watt light bulb the 2270 doesn't do anything but the bulb glows at full blast... not good. With the 2270 plugged into the wall it blows the fuse, but with the bulb tester it won't even do that. Need to thoroughly check this transformer.

 

[bhmav8r]

1µF WIMA with long leads: https://www.mouser.com/WIMA/Passive...Z1z1416fZ1z0vn48Z1z0zldhZ1z0x6fr&Ns=Pricing|0

Thankyouverymuch!!!

 

[bhmav8r]

Whats the usual on all the FM boards?
Just recap them or are there some diodes and transistors that should be addressed "while i'm in there"
Haven't seen much on this as the other boards.
As always - TIA

 

[Steven Tate]

Many people leave the tuner boards alone. I replace electrolytics, and I use WIMA films for capacitance 4.7 uF or below if they will fit. I leave everything else alone. I have seen posts that say this could mess with alignment. I haven’t found that to be the case, but my experience is limited to about a dozen units.

 

[Leestereo]

IME, replacement of the electrolytic capacitors on the FM boards has not impacted their alignment.

 

[Mike Sweeney]

Many people leave the tuner boards alone. I

I rebuild every one of them I work on. They always work better after being recapped. I dont find many issues other than the old caps drifting to the high side of their value. I'm at a dozen ish too.. no issues with recapping.

 

[quadklipsh]

Lee what are the pre and post recapping impressions of this amp.
I owned a 2230. So im interested .

 

[Steven Tate]

I have gone back to a filthy 2270 that has been sitting on a shelf for about three years, using this thread as a guide. I have removed the caps from the power supply board and replaced the diodes that were recommended. I've also replaced the main filter caps. I'm waiting on a Mouser order with the upsized P800 caps recommended by Leestereo. In post #2, there is a recommendation to replace R801, which is on the chassis, and there is a photo. My unit does not have this resistor on the chassis. I did find a big 150 ohm resistor on the board with no silkscreen marking, and I'm assuming this is R801. Just wanted to check and see I have this right. If so, should I replace the resistor, or is this cement type of resistor likely OK if in spec? Thanks!
Steve

My chassis where R801 was on Leestereo's.


What I assume is R801

 

[Leestereo]

...there is a recommendation to replace R801, which is on the chassis, and there is a photo. My unit does not have this resistor on the chassis. I did find a big 150 ohm resistor on the board with no silkscreen marking, and I'm assuming this is R801. Just wanted to check and see I have this right. If so, should I replace the resistor, or is this cement type of resistor likely OK if in spec?

What I assume is R801
View attachment 1511809

Yes, the cement resistor on the board is R801. I would still recommend replacing it a 7W enamel type (e.g., https://www.mouser.com/ProductDetai...onics/W221500JRLF?qs=eJe21KOba0T0TayUqQzDfQ==) since it is a smaller size (better air flow for cooling) and has a much lower TCR.

 

[Steven Tate]

Yes, the cement resistor on the board is R801. I would still recommend replacing it a 7W enamel type (e.g., https://www.mouser.com/ProductDetai...onics/W221500JRLF?qs=eJe21KOba0T0TayUqQzDfQ==) since it is a smaller size (better air flow for cooling) and has a much lower TCR.

Great! I have some of those in stock. Hope to get the larger caps for the P800 board in the next couple of days to give it the first test. In the mean time, I'm Deoxiting switches and pots and doing a general cleaning. This unit is very dirty on top. But it played in all modes before starting - just sounded terrible. Hoping for the best. Thanks!

 

[jFF_Bulbo]

Hello

I am restoring my 2270. Should the h760 (nte 295 or mje) have Mica insulator?
Regards

 

[Steven Tate]

Yes, there is a round mica washer about 10-12mm or so between it and the heat sink. I got them from Mouser - part no. 534-4678.

 

[Steven Tate]

I'm working on the right amp board of a 2270 and trying to follow Leestereo's recommendations on page 1 of this thread. In the past, I have replaced the electrolytic caps, the tantalum cap and the diff pair and called it a day. He replaces several other components with modern equivalents, and I'm giving it a try. He replaces two carbon composition feedback resistors, R757 and R759 with 1% metal film resistors. I dug through my parts and found a 100k ohm, 1/2 watt metal film resistor, and it is tiny - 1/4" long at best. It's hard to believe this tiny thing will handle a half watt of power, but I'm guessing it will. Just thought I would post a pic of it next to the beefy 1/2 Watt CC resistor at R759, . and let you guys tell me if this is a suitable replacement. Photo of the label is included. Thanks!
Steve

 

[thornev]

How well do these upgrades apply to a 2265B serial 88P110110 ? Should be pretty close as it's still a 22xx series, right? Thorne

 

[Leestereo]

...I dug through my parts and found a 100k ohm, 1/2 watt metal film resistor, and it is tiny - 1/4" long at best. It's hard to believe this tiny thing will handle a half watt of power, but I'm guessing it will. Just thought I would post a pic of it next to the beefy 1/2 Watt CC resistor at R759, . and let you guys tell me if this is a suitable replacement...

The small form factor 0.5W metal film resistor can be used in this application (i.e., feedback duty) without any issues. Note that the original resistor is a carbon film type rather than a carbon composition type. For metal film resistors that are closer to the vintage sized originals, I often use KOA Speer MF1/4 and MF1/2 (https://www.mouser.com/datasheet/2/219/MF-MFS-RK-18760.pdf).

 

[Steven Tate]

The small form factor 0.5W metal film resistor can be used in this application (i.e., feedback duty) without any issues. Note that the original resistor is a carbon film type rather than a carbon composition type. For metal film resistors that are closer to the vintage sized originals, I often use KOA Speer MF1/4 and MF1/2 (https://www.mouser.com/datasheet/2/219/MF-MFS-RK-18760.pdf).

Thanks! I had already gone back and looked at the specs on that tiny resistor and found that it was a 5% spec. In looking for a 1%, I found those KOA Speers. I’ll probably go ahead and order some to look a little better and have a tighter spec.

 

[Leestereo]

How well do these upgrades apply to a 2265B serial 88P110110 ? Should be pretty close as it's still a 22xx series, right? Thorne

The 2265b is a 3rd generation Marantz 22xx and as such its topology is significantly different from the earlier generation 2270. Nevertheless, the same type of upgrades, e.g., increasing DC filtering capacitors, film/C0G capacitors for the signal path, are applicable to all vintage units. These Marantz restorations/upgrades are for models which are closer to the 2265b topology: Restoration and Upgrade of a Marantz 2235B Receiver, Leestereo's Restoration and Upgrade Of A Marantz 2325 and Leestereo's Marantz 1090 Restoration/Upgrade.

 

[jFF_Bulbo]

Hello AK'ERS
i AM restoring my 2270. I have changed about 90 pieces.
Once i finished, i tried to test bias on j756/754. (Right channel) As soon as i powered the Unit R787 ON LEFT channel exploded. Nothing bad happened on the right channel.
Any idea about the problem?
I followed this -absolutely amazing- post about upgrade and restore.
I am worried about a damage in other components .
Thanks in avance for your help.

 

[patfont]

You would want to test that across the emitters:

J754/J760 @ 10mV

adjust R763

 

[Leestereo]

@jFF_Bulbo: did you replace the output transistors in the left channel? Go over your work (e.g., orientation of replacement components, solder bridges, etc...) and and compare with the working right channel. Also recommend that you build a Dim Bulb Tester (DBT) and use for the next time you power up the 2270.