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Lou - N2MIY
October 22nd, 2009, 05:13 PM
Folks,

I am looking for the RA80 Service Manual: EK-ORA80-SV. It's not on bitsavers, manx, or the other usual places. I was given an RA80 that had worked for its previous owner, but now it has trouble spinning up. It gets up to about 25% speed, then the spindle motor cuts out and the controller gives either error 1 or 4 on the internal leds, and flashes the spinup error on the front panel lights. I scoped the speed sensor, and it is OK. Same behavior when trying to run the 1E internal diagnostic (manual spindle motor control). The maintenance guide and user manual do not provide enough detail.

I really need the service manual to understand all the interlocks that could cause the spindle motor to drop out during spinup. I have a KDA50 (qbus SDI adapter) and would like to get this drive running.

If someone has this manual I would appreciate your help in getting a copy.

Thanks,

Lou

PDP11GY
October 27th, 2009, 01:30 AM
Hello,
the information you need is on :
http://bitsavers.org/pdf/dec/disc/ra80/
Reagrds, Reinhard

Lou - N2MIY
October 27th, 2009, 02:04 AM
Hello Reinhard,

Thanks for your reply. Actually, the RA80 service manual is not on bitsavers. Only the users guide, maintenance guide, and FMPS. I was sure to check bitsavers and manx before making this post.

I put out the same call on alt.sys.pdp11 and it was suggested that I look at the RA81 service manual, which is on bitsavers. It was thought (correctly) that the spin-up logic would be the same.

So, I am making progress. I have tracked the problem back to a suspect 8155 from which comes the spindle motor start and run signals. We'll change that and see what happens - the rest of the downstream circuitry to the motor works properly.

Lou

pontus
October 27th, 2009, 03:58 AM
I'm glad to hear that you are making progress. I have three RA80 that I will at least try to get going sometime in the future. I have some documentation, but it's all in storage and I don't have a faintest of what it is.

nige the hippy
October 27th, 2009, 08:48 AM
will the RA81 diagnostic/maintenance manual at

http://vt100.net/mirror/hcps/m879btc.pdf

help? (it takes a while to download)

Lou - N2MIY
October 27th, 2009, 03:25 PM
Pontus,

With enough patience, I'll get this RA80 working. It did spin up once, and worked for Tim (who was it's former owner). I feel like rather than calling ourselves owners of this dec gear, we should call ourselves "resident field service engineers".

I picked up off ebay an RA72 and what ended up being an RA73 (I thought I bought two RA72s, but I looked closely) They are a bit smaller than the RA80, but who wants small? I assume you have a KDA50 or UDA50? This is my first experience with SDI disks. Qbus SCSI adapters are soooo expensive, perhaps SDI will be the poor man's scsi (I got the KDA50 for far less $$$ than a RQZX1 could ever be.) If only there was an SDI CDROM.....

Nige,

I have the analogous maintenance manual for the RA80. The RA81 manual does not seem to be any more meaty, but thanks for sending the link.

Lou

pontus
October 27th, 2009, 11:38 PM
I feel like rather than calling ourselves owners of this dec gear, we should call ourselves "resident field service engineers".

Indeed :D




I assume you have a KDA50 or UDA50? This is my first experience with SDI disks.


At the Moment I only have a UDA50 sitting in my VAX 11/750. I would like to have a KDA50 to test the drives on a smaller VAX or PDP-11 first (before getting the 11/750 to run).

tradde
October 28th, 2009, 04:13 AM
Indeed :D

At the Moment I only have a UDA50 sitting in my VAX 11/750. I would like to have a KDA50 to test the drives on a smaller VAX or PDP-11 first (before getting the 11/750 to run).

I have a UDA50 on my 11/84. It works quite well with the few SDI disks I have. Too
bad the one Eagle I had hoped to find bootable doesn't like to come ready. I have
tried figuring out why, but there is not alot of documentation available for Fujitsu
Eagle drives. I have found some, but it's more how to use and set up than debugging
and fixing. It will come ready for very short periods at times, but then loses it. I don't
know if this means the servo is not finding track zero correctly, or if something else
is wrong. I am not as much of an engineer as othes here, so it's not as easy for me
to figure this stuff out.

Lou - N2MIY
November 8th, 2009, 04:11 PM
Well, after dinner this evening we powered up the RA80 after replacing the offending component. The RA80 is controlled by an 8085 microcontroller and uses 8155 I/O expanders. The 8155 that controls spindle motor operations was flakey.

So, we changed that bad boy and the drive spun right up to ready.

We had a good weekend - I found the problem with my KDA50 (the lousy 50 conductor inter-board cable) and fixed a broken VT102 I had been given (broken +5V power supply pass transistor AND replaced the flyback when it broke 15 minutes after I fixed the PS (but used up my last spare VT100 flyback).)

Lou