Anyone have/know of Persci drives, parts

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Mon Jul 26 16:33:39 2004

>
> Subject: Re: Anyone have/know of Persci drives, parts
>
> 1. There are no microcontrollers on the 270/277 series drives (I believe
> that there were on the later 299 drive)

OK< I've only seen on Persci drive, that on my CASU Super C S100 system,
and I can't remember what model it is. I do remember a 40 pin EPROM
microcontorller (with a quartz window), which iIRC was an 8748.

>
> 2. The board has a huge amount of analog circuitry on it, both for the r/w
> head and the very complex servo system, and is not easy to troubleshoot.

I really can't believe it's impossible, or indeed any worse than many of
the things I've worked on. From waht I remmeber, the servo circuitry is
similar in concept to that in, say, an RK05 drive, and I've worked on
those.

>
> 3. None of the components on the board, including the 50 or so ICs, are
> socketed.

None of the 1000+ ICs in my PDP 11/45 CPU (including the MMU and FPU) are
socketed. This has not stopped me repairing it. Actually, I am not sure
what benefits socketed ICs provide for troubleshooting/repair --
desoldering and replacing the faulty IC is not a major job, and you
shouldn't need to remvoe ICs other than the faulty one (in other words
troubleshooting should not consist of replacing ICs until the thing
starts working).

>
> No argument that the boards ultimately could be repaired, but it's not
> nearly as easy as your post suggests. Plus there are 4 other major but

I will admit I've not worked on this model of drive. But I have worked on
things of greater complexity -- without service information -- and got
them going. I am darn sure this board can be repaired.

> smaller boards on the drive in addition to the large main board.

-tony
Received on Mon Jul 26 2004 - 16:33:39 BST