Heathkit H-11 restoration questions

From: allisonp_at_world.std.com <(allisonp_at_world.std.com)>
Date: Mon Oct 4 12:16:22 1999

> > RXV11 is only compatable with the DEC RX01. The H11 Floppy used a Heath
> > interface. If you use the heath floppy with RXV11 nothing happens.

By nothing happens I mean no harm, not useful.

> OK. I'll go back to the card and get it working. Worst case, I'll pull
> all the sockets and solder in machine-pin ones. I'd rather not; it's lots
> of work. I observed substantial oxidation of the plating on the ICs I did
> remove and test (I can't test DEC bus chips with my IC tester, only CMOS,
> TTL and DRAM).

It's unlikely there are bad chips. bad sockets however are teh bain of
heathkits.

Manuals try heathkit of whatever their name is now.

> It looks dodgy, but then most of the Heath stuff looks less solid to me.

It worked. But it was nowhere near as durable as the DEC cards.

> Don't got it. I have several 32Kw and 128Kw boards from 11/23s, etc., and
> a few 4kW and 16kW boards from my LSI-11s (knee-high formica-topped rolly
> DEC cabs w/RX01 and 11/03 inside).

Just about everyone upgraded to 11/23 and dec cards for performance
reasons.

> The card itself is about as simple as any Qbus card. It is, I take it,
> supposed to be nominally RXV11 compatible from a driver standpoint, yes?

Yes, RT11 DX (rxv11). The card relies on the heath drives being smartend
with a z80 card in them. If you have the heath drives the hub clamps
and pressure pads should be inspected.

> If not, then that's part of my problem. I do boot, the disks to appear to
> read in an OS, then the system hangs, but that could be as a result of my
> card only working if it is *not* at the end of an unbroken grant chain (with
> a gap in the bus, the disks read but the system does not boot; without a gap
> in the bus, the CPU does not even bring up the boot message).

That or not enough memeory or the console card at wrong address or RTC
enabled.

> So far, the only problem I appear to have is that the belt on DX1 has either
> broken or fallen off. The motor is turning, but not the hub. I haven't
> pulled the drive to check yet. On the bright side, the mechanisms appear to
> have a 50-pin edge connector, suggesting that they are standard from that
> standpoint. I expect that the hub motors are either 110V or 24V.

Fairly standard, you might get other drives to work but jumper settings
are not in my known info.

> I did spot the obvious format switch on the front of the disk unit, but no
> idea how to use it. I now wish that I'd picked up a couple more boxes of
> media from a friend's business about eight years ago. He had a pallet of 8"
> disks that he was selling for more money that I was willing to pay.

The switch enabled formatting but you needed the heath format program
if memory serves.

> One of the gems I have in the Heath pile is an unassembled backplane. I don't
> know if all the connectors are there or not and I don't have a second case
> for it, but I've got at least part of one to "attract" the rest of it.

;) Mine is complete and I knew the original owner (and same for most of
the boards). What I have has been following me for close to 18 years and
are original from back 1979!

FYI 11/03 cpu cards are common as house flies. Same for standard DLV11,
and DEC memory, heath cards are scarce and often have socket problems
or look like they were soldered with a torch.

Allison
Received on Mon Oct 04 1999 - 12:16:22 BST