Is there any reason a Riso GR drum will not work on an FR3950?

**Engelgrafik** · 07-11-2013

Some of you might remember I recently acquired a bunch of Riso equipment. An FR3950, a GR3750, a bunch of FR/GR drums, GR drums, an RC drum and three RP drums. Besides the FR3950, which runs perfectly now (thanks to a Riso tech), all of that equipment was acquired as a big lot which had been sitting in a garage for "1 year" (as the seller told me when I was looking at the equipment... but probably more like 3 years).

Anyway, I recently had the nearby Riso tech come out to fix my "paper jam" and stuck drum. It as a teal GR drum that was stuck. He removed it and then looked at the fuse and it was blown. He did some work, replaced the fuse, made registration adjustments on the back, did a bunch of other stuff, put the original FR/GR black drum in there and it worked. Then we tried the FR/GR green drum and it worked too. Perfect. Then I showed him my other drums...

I've cleaned up a bunch of the drums but the Riso tech said the GR drums don't really work in the FR machines. I told him that was strange because the guy I bought all the equipment from said the GR drums will work on an FR, and I had heard from many web sources that the GR drums do work on the FR machines. He said maybe his memory is wrong, had hasn't worked on GR and FR machines in a long long time. So when we went to put a bright red GR drum in my newly working FR3950, nothing happened... It wouldn't print. I said, "oh this might be a bad drum... I've been trying to clean them but I don't know how good a job I'm doing". He said the fact that it didn't even rotate (even though it rotates manually by hand) makes him wonder maybe we blew another fuse. Sure enough, the same fuse that he replaced a minute before was blown.

Anyway, long story short, I'd like to verify... is there any other reason why a GR drum wouldn't work on an FR drum? Or is it possible that my GR drums are in really bad shape?

What does everyone use to clean their drums? I took some advice from other threads and actually got a gallon of diesel fuel and rags. This really helped clean ink and even rust off the drums and hardware, however I didn't really get into the drum to see what's going on inside. Maybe I should...

Any recommendations or thoughts on this would be appreciated. I would really love to salvage these drums.

Otherwise, I have to figure out how to sell these for parts. Or what to do with them if I don't even have that option. I do have to sell the RP drums... and I believe the RC drum doesn't work on the GR or FR machines.

**jermyth** · 07-11-2013

If the drum is the same size, ledger I think, then it should work.
But if you are blowing a fuse when you swap drums, then you got bigger problems. Short in the drum harness or bad spot on the motor causing the over load. Which fuse?

**Engelgrafik** · 07-12-2013

Originally Posted by jermyth

If the drum is the same size, ledger I think, then it should work.
But if you are blowing a fuse when you swap drums, then you got bigger problems. Short in the drum harness or bad spot on the motor causing the over load. Which fuse?

It's the "F5" fuse (I'm looking at the tech manual which the guy let me download from his tech account), which is the 3rd one from the right.

I think I'm going to start taking apart as much as I can and really clean these things good. Look at the wires and try and separate them all as well as I can. I have anti-oxidation spray (which I use for my guitar electronics.. it's awesome), some citrus degreaser and the diesel. Any other recommendations?

**20gaugeO/U** · 07-12-2013

GR came first. FR after. GR/FR drums were backwards compatible but I doubt GR works in FR. Take the lower front plastic cover off (4 screws off) and look at the PCB's. Check all the for the oversized part number stamped on each GR, FR, GR/FR drum. Doubt they are the same.

Or you have something major like Jermyth mentioned and it would be cheaper/easier to find a new drum.

**Engelgrafik** · 08-23-2013

Well I've cleaned and de-rusted a bunch of GR drums and so far only my bright red GR drum blows the F5 fuse. A GR Burgundy works great in my FR3950. So I think it can be said that GR does work in FR machines.

Originally Posted by 20gaugeO/U

GR came first. FR after. GR/FR drums were backwards compatible but I doubt GR works in FR. Take the lower front plastic cover off (4 screws off) and look at the PCB's. Check all the for the oversized part number stamped on each GR, FR, GR/FR drum. Doubt they are the same.

Or you have something major like Jermyth mentioned and it would be cheaper/easier to find a new drum.

**Teikaut** · 12-03-2019

I want to follow up on this thread to say that I also have a FR3950, and have had a similar experience. I have had a GR Burgundy drum work fine, but had a GR Blue drum lock up in the machine and throw the timing off. While it may be possible that the drums can be interchangeable, I see that you've had the same issue that I have with your machine and I wonder if it's because of the GR drums.

**bgerssen** · 01-18-2020

Check the switch settings, for GR they're different than for FR. The switches are in front of the drum underneath the plastic cover which you need to unscrew first. You can find the proper settings somewhere on the internet. Good luck!