Monthly Archives: May 2015

Retr0bright pt. 2

Took a fair bit longer than anticipated because a) not much sunshine b) I got the mixture wrong c) very yellow

not so yellow

Not completely done but considerably better. I think the rest shall get a dunking and a sunbath. I do have a UV lamp but I don’t think it’s energetic enough to work.
Some people don’t like the whole Retr0bright thing because it detracts from the device. I don’t think so in this case. The keys are double-shot (the black is molded separately to the white, the black shows through, can’t wear off etc.) so there is a caution to be had in bleaching the black of the keys down to something more pale.
With the keys all white, it’ll look considerably better to my eyes. That’ll count for now.

Retr0bright

Mixed up a batch of Retr0bright and stuck a keycap in it outside in the sun, held down by a pair of tweezers (it’s plastic so floats in the solution)

retr0bright

Shall leave it outside for probably 30 minutes or so, it’s a on-and-off sunny day with a number of clouds.

If it works nicely I’ll do the rest on a slightly larger scale.

More Lanier

After the Qume printer took out the 5V rail on the Lanier’s PSU (The thing is powered from the computer rather than with its own power supply) I desoldered the failed transistor, replaced it with the last remaining one and powered back up:

five volts

Thankfully that worked.

Replaced everything into the chassis, as it was too heavy with everything in to carry. Even with the PSU, cards and floppy drives removed it was a strain to get it in and out of the car.

beep

Back up and where we were at before. Current plan is to replace the onboard 512 byte PROM that it boots from with a modified rig with a larger EEPROM, the extra address legs that the system doesn’t natively use to create pages of code available (16 thereof with the $4 EEPROM) which would be addressable via software. Shadow ROM.

Need to get some flip flops and a couple ZIF sockets and some breadboard and get this built. I’m excited to be able to see if it’ll begin to do sensible things.

Pop, crackle, fizz.

Continuation of the Lanier Diaries here, decided to bring the Lanier up gently on the Variac to see if the lack of printer was the cause of it not booting.

Did so, net result was the printer smoking up and taking the +5V power rail with it. Possibly the root cause of the initial failure.

burned qume

Took the Qume apart and cleaned it out. There were a few nuts and bolts rattling about inside on the circuit board. That might have been part of the reason also.

I shall henceforth be fitting fast-blow fuses to the 5V rail.

Much storage space!

I hacked a few through-hole components onto the board to get it working last night.

Back of board

Also hacked an IC socket to fit so I could put the remaining chip on.

Front of board

Had a bit of a headache partitioning the CF up. Diskpart under WinXP (The machine I have that had a CF socket runs XP) doesn’t recognise the CF as a disk, but as a “Removable” device, so refuses to do anything with it. In the end I went got GParted and booted up into that. Thankfully it read the CF and I was able to slice it up. There’s a bit of lost space (About 1.7Gb) because DOS takes a loooooooong time to read the free space with an 8088. Or a V20, in this case. So, there’s a 512Mb drive at the front and 3 2Gb drives at the back. I might experiment with an extended partition and see how it handles it. Maximum 4 primary partitions!

Fired up the 386 to assist in copying stuff from the old drive onto the new.

copycopycopy

Plugged it into the 8088.. it booted right up (so quickly!). Really good deal.

Still, it’s odd to see this on an old green-screen..

More than 1.21 Gigabytes, Great Scott!

2Gb free? Took about 40 seconds to decide that also. Next up, trying to figure out what’s crashing due to heat. I think the video card was having issues because yesterday evening, with the lid off, it was overheating. I need really now, having proven it, to mount the CF card directly to the IDE board. There’s enough space inside. Also, I might remove the LED and bring it up front to the little window.

Compaq – RAM and Compact Flash

I’d been after a RAM upgrade for the Compaq for a while. The spare parts arrived in yesterday so I started work on the IDE/CF adapter:

Lo-Tech CF adapter and parts

Typically, I’d missed ordering two pieces in a hurry and accidentally broke one of the SMC capacitors on the back because they are fiddly.
This is one of the bigger bits, one of the chips:

SMC NAND gate

Got it soldered on the board:

SMC chip onboard

Gave up after putting the through-hole components on as I’ve had to order the missing parts. Stuck the RAM in on the expansion board, got it set up and the RAM report is good now (was 512k):

Should be enough for everyone.

Waiting on the spares to come in. The Compaq has decided not to boot any more, think possibly the RAM or the hard drive has quit.

Lanier Diaries, Part XV

I’d placed an order for some replacement 4116 DRAM. Apparently these days it’s really hard to source so I took a looksee and found a couple guides that show how to use 4164 (more common) DRAM in the same sockets.

Some 4164 was ordered from Jameco Electronics in California.

DRAM

This guide, called “4116 to 4164” was the one I used to convert the 4164 to be able to be used in a 4116 socket. The 4116 has one less address line so the RAS/CAS allows for 4x the amount of memory in the 4164- we just don’t use one address line (tie it high) and connect up only the ground and +5V, compared to the +12, +5 and -5 supplies the 4116 needs.

Fit them in place:

4164 in 4116 sockets

Powered up and BEEEEEEEEEEEEEEEEE, same result.

Continuation of troubleshooting to follow.