What vintage computer modifications have you performed recently?

[00WReX]

Yeh, i was lucky enough to get a CoCoSDC back in late January / early Feb.

It is very cool. I also picked up a couple of Glenside IDE boards that work

great, I really like those. I had to get some CoCOEPROMpak PCB's made up

which was cool as I'd never had PCB's manufactured before.

 

Some of the bit's & pieces I have done in the last month or so...

 

My CoCo 1 started to have a lockup isssue soon after switching on.
I replaced the memory chip in position U21 to fix issue.

 

Fitted a cloud-9 512K SIMM memory upgrade into my CoCo3, sent photo's back to

cloud-9 nine as they had not seen the PAL mainboard with the slightly different

component layout, a the 2 capacitors that get clipped are in a different position.

 

Upgraded one of my Tandy CoCo 2's (26-3136B) to 64K using 2 of the 41464 chips
from the CoCo 3 that I upgraded. The mainboard also requires a jumper for 64K.

 

Modified a CoCo Rom Pak case to fit the CoCo SDC board.

 

Ordered 3 CoCoEPROMpak PCB's from OSH Park. Wanted them for the 2 Glenside IDE
boards I purchased from the Glenside CoCo club in the United States

 

For fun decided to try a Chinese PCB place called itead studio.

10x CoCoEPROMpak boards for just over $22 AU delivered was very good I thought.

 

Fitted a jumper to LK4 on all 3 of my Acorn Electron main circuit boards to provide colour

on the composite video out (normally composite is only B/W on the Electron).

 

Made a SEGA SC-3000 multi cart by modifying an existing cartridge (Safari Hunting).
Removed the 28 pin game chip and fitted a 32 PIN 1MB EPROM with 32 x 32KB games,

selectable via a dip switch. Programmed the EPROM with my choice of games.

 

Made a C64 EayFlash cartridge from a kit I purchased.

 

Various cables & connectors (such as another drivewire cable), that's all I can think of at the minute.

 

Cheers,

Shane

[jmetal88]

The oldest CoCo drive interfaces require 12v which the CoCo 2/3 don't have.

 

 

Actually, if you get one of those older drive controllers (as I did, because someone was selling unhoused PCBs of those controllers for quite cheap on eBay), there's a mod you can do that eliminates the need for 12V. I can't recall the details right now, but I did the mod to mine a while back and it worked great! If I remember correctly, all it involved was replacing the controller chip with either a slightly newer version of the chip or a similar chip and maybe cutting a few traces. I'll have to take the controller out of its makeshift case sometime soon and look it over to try and remember the exact details.

 

EDIT: Actually, I was remembering incorrectly. When I first bought the controller, I had jumpered in 12V from an external source to get it to work, so what I was thinking I had removed was actually just that jumper. I didn't cut any traces. If you want to change it to 5V-only operation before using it, all you have to do is pop out the WD1793 controller chip and replace it with an MB8877A.

Edited May 20, 2014 by jmetal88

[JamesD]

Actually, if you get one of those older drive controllers (as I did, because someone was selling unhoused PCBs of those controllers for quite cheap on eBay), there's a mod you can do that eliminates the need for 12V. I can't recall the details right now, but I did the mod to mine a while back and it worked great! If I remember correctly, all it involved was replacing the controller chip with either a slightly newer version of the chip or a similar chip and maybe cutting a few traces. I'll have to take the controller out of its makeshift case sometime soon and look it over to try and remember the exact details.

 

EDIT: Actually, I was remembering incorrectly. When I first bought the controller, I had jumpered in 12V from an external source to get it to work, so what I was thinking I had removed was actually just that jumper. I didn't cut any traces. If you want to change it to 5V-only operation before using it, all you have to do is pop out the WD1793 controller chip and replace it with an MB8877A.

 

Know a source for the MB8877A?

[jmetal88]

 

Know a source for the MB8877A?

 

eBay.

 

http://www.ebay.com/itm/LSI-MB8877A-Fujitsu-Floppy-Controller-40-Pin-8877P-/370288360080?pt=LH_DefaultDomain_0&hash=item5636e7fa90

[MarkO]

JamesD, 00WReX, and jmetal88, Thanks for the Links and Input.

I found some drives on eBay, FD-501/FD-500 and FD-500. They are a little more than I am planning on spending, right now..

I see the MB8877A's are on Sale, the next Two days.. Maybe I should get a couple, for potential modifying future TRS-Drives

 

What Model Numbers are the Older, Full Height, Vertical Drives?? Maybe like this one, model #26-3022 or this one Model 26 3029??

I took a few Photos of my CoCo 3 and placed them is a Gallery, Tandy CoCo 3.

[jmetal88]

I see the MB8877A's are on Sale, the next Two days.. Maybe I should get a couple, for potential modifying future TRS-Drives

 

Well, those chips are for the controllers, not the drives. You need a controller cartridge to plug into the side of your CoCo, then a ribbon cable runs from that to whatever drive you're using.

[JamesD]

JamesD, 00WReX, and jmetal88, Thanks for the Links and Input.

I found some drives on eBay, FD-501/FD-500 and FD-500. They are a little more than I am planning on spending, right now..

 

I see the MB8877A's are on Sale, the next Two days.. Maybe I should get a couple, for potential modifying future TRS-Drives

 

What Model Numbers are the Older, Full Height, Vertical Drives?? Maybe like this one, model #26-3022 or this one Model 26 3029??

 

I took a few Photos of my CoCo 3 and placed them is a Gallery, Tandy CoCo 3.

Drives with controller used to be $50-$75. I have to think that is a temporary jump.

 

The 26-3022 looks like an original unit. They don't hold their speed very well an you have to adjust them once in a while or they screw up your disks. I've had one since I was in high school and it was a PITA!

The other model should work with a CoCo controller. I'm not sure if it was a CoCo drive or a Model IV external drive. Doesn't really matter, it looks like a better mechanism than the original. The original has the button on the front you push down on to open the drive.

 

[MarkO]

 

Well, those chips are for the controllers, not the drives. You need a controller cartridge to plug into the side of your CoCo, then a ribbon cable runs from that to whatever drive you're using.

 

Thanks for the Clarification.. I am Very New to the CoCo's

[MarkO]

Drives with controller used to be $50-$75. I have to think that is a temporary jump.

I am still waiting for the jump in Classic Apple parts to drop.. Ever since Steve Jobs died, most of the eBay sellers think Old Apple Stuff was Hand Packaged by Jobs..

 

The 26-3022 looks like an original unit. They don't hold their speed very well an you have to adjust them once in a while or they screw up your disks. I've had one since I was in high school and it was a PITA!

The Original Disk ][ for Apple are the same way.. There is a little Multi-Turn Pot to adjust the Speed..

 

The other model should work with a CoCo controller. I'm not sure if it was a CoCo drive or a Model IV external drive. Doesn't really matter, it looks like a better mechanism than the original. The original has the button on the front you push down on to open the drive.

It does look like the Model IV.. I had a friend that had the Model III and then the Model IV, and then the Tandy 2000 ( MS-DOS compatible Machine, not IBM PC Compatible )

[jmetal88]

You don't have to be too picky about the drive you use with your CoCo controller. You can even use a PC drive if you want to, but you'd probably have to construct your own case and power supply for it. Bear in mind that a 1.2MB drive is going to be useless, though. A 5.25" 360k drive will work, a 3.5" 720k drive will work, and a 3.5" 1.44MB drive will work (provided you use 720k floppies or tape over the density hole of the disks you use). The third option is what I went for, and I housed it in one of the larger Radio Shack project boxes. I even added a switch and some circuitry to invert the 'side select' line so I could use both sides of the disk in Disk BASIC. It's like having a 'flippy' disk that you flip with a switch instead of physically flipping the disk. I need to reconstruct the thing at some point, though, as I took it apart a while back to use some of the parts for something else. I do have a couple of original single-sided Tandy disk drives, but they're in such awful shape that I never use them. The newer one doesn't work at all, and the older one does work but has a really rusty case. I took the older one apart to re-paint it at one point, but since the 3.5" drive was working so well (and I have no original software that requires the 5.25" drive) I never actually put it back together after I finished painting the top half.

[MarkO]

Drives with controller used to be $50-$75. I have to think that is a temporary jump.

 

The 26-3022 looks like an original unit. They don't hold their speed very well an you have to adjust them once in a while or they screw up your disks. I've had one since I was in high school and it was a PITA!

The other model should work with a CoCo controller. I'm not sure if it was a CoCo drive or a Model IV external drive. Doesn't really matter, it looks like a better mechanism than the original. The original has the button on the front you push down on to open the drive.

Do you have any Directions on Adjusting the 26-3022 Analog Disk Controller???

 

I have one I bought, and have replaced the WD WD1793B-002 with the Fujitsu MB8877A and connected it to a FD-500 with a single Drive..

( See Album Tandy CoCo's 001 )

 

The 26-3022 Disk Controller was Surplus from the Tandy Surplus Store in Fort Worth, TX, so it most likely new, the FD-500 is very low usage, owner claimed used less then 10 Hours.. It Looks like new, Warranty Sticker still in place and no ware..

[JamesD]

Do you have any Directions on Adjusting the 26-3022 Analog Disk Controller???

 

I have one I bought, and have replaced the WD WD1793B-002 with the Fujitsu MB8877A and connected it to a FD-500 with a single Drive..

( See Album Tandy CoCo's 001 )

 

The 26-3022 Disk Controller was Surplus from the Tandy Surplus Store in Fort Worth, TX, so it most likely new, the FD-500 is very low usage, owner claimed used less then 10 Hours.. It Looks like new, Warranty Sticker still in place and no ware..

The drive needed adjustment, not the controller.

There was supposedly a bug in the controller that someone had a fix for. I think it just involved adding an IC and some jumper wires but I have no idea where the info is.

 

 

Adjusting the drive is a matter of opening the drive, holding an AC lamp with a regular bulb or a strobe light near the drive and adjusting a pot until the marks on the drive hub appear to stop rotating.

 

[Junosix]

Fitted an HxC Slim floppy emulator into the floppy drive space in my STE.

[MarkO]

The drive needed adjustment, not the controller.

There was supposedly a bug in the controller that someone had a fix for. I think it just involved adding an IC and some jumper wires but I have no idea where the info is.

Ahhh... I was confused by the Fact the 26-3022 Controller Card has Three 100Kohm adjustments along the one Card Edge.. The Later Cards do not seem to have them, although they might just be a Lower Profile on the Circuit Board..

 

If you come across any Fixes for the Bug in the Controller, I would be curious about seeing it...

 

 

Adjusting the drive is a matter of opening the drive, holding an AC lamp with a regular bulb or a strobe light near the drive and adjusting a pot until the marks on the drive hub appear to stop rotating.

I have seen pictures of the Original Apple ][ Drives, made by Shugart that have those Timing Marks..

 

 

I always use the VERIFY DRIVE SPEED feature of Copy ][ Plus 5.5. You install a Scratch Disk, it moves the Read/Write Head to track 35 and Writes a bit pattern, then Reads it back, while timing it.. Your Disk ][ should be at 200ms, Plus or Minus 2ms. A Multi-Turn Potentiometer is on the Spindle Control Board, and is adjusted to get your Spindle Rotational Speed correct...

[Uzumaki]

Some C64 disk drive also have the marks for adjusting. They have 60hz and 50hz marks depending where you live to adjust.

[RobertB]

I added a 256 meg ZorRAM to the Amiga 3000 a few months ago and have just bought another 256 meg ZorRAM to put into the Amiga 4000.

 

Last day in England before returning to California,

Robert Bernardo

Fresno Commodore User Group

http://videocam.net.au/fcug

July 26-27 Commodore Vegas Expo v10 -

http://www.portcommodore.com/commvex

[MarkO]

I just Modded my CoCo Skiing Cartridge, removing the ROMs, and replacing them with Sockets.. I am thinking I want to put HDB-DOS in EPROM, so I can set up Drive Wire to transfer CoCo Disk Images from my Windows or Mac to the CoCo 2 or CoCo 3.

[82-T/A]

Well, I don't really think it's Vintage in the sense you guys mean... but a year ago, I bought an old Dell 325P computer... it was a very specific model that I was looking for because it was their first small form factor PC, and I didn't want a huge behemoth to play old games on. Basically, it's a 386 SX-25 that came with a 40mb IDE hard drive and 1mb of ram.

 

I swapped out the 40mb drive with a SSD DOM (Disk on Module) that plugged right into the IDE port. I then bought a Sound Blaster 16 ASP w/ Yamaha General Midi daughter board, and a Panasonic IDE-style CD-ROM drive connector. I then installed a double-speed Creative Labs (Panasonic) CD-ROM drive, and a 3.5" floppy drive. I then also bought a 16-bit w/4mb of ram graphics card... ATI VGA Wonder. I also installed 8mbs of ram (60ns), and then finally dropped a Cyrix 486DLC chip in place of the SX processor (removable).

 

It runs the equivelant of say a 386 DX, but I can speed it up to say a 486 / 25mhz sped when I enable the cache. It allows me to basically play all of my old DOS games as they were meant to be played, without having to use DOSBOX or any of that nonsense.

 

FYI, I have DOS 5.0 installed, along with GeoWorks and Windows 3.1 (for Castles of the Winds and stuff).

 

I use that system to play games like all the old Advanced Dungeons & Dragons gold box series games, Starflight, Sentinel Worlds, etc.

 

 

 

My other computer is a small mini-tower, an Acer Altos 1000, with dual Pentium II - 233mhz processors. It's got 256mbs of ram, a 1 gig SSD drive, and then another 40 gig drive. It's got an SCSI 8x CD rom drive, a Sound Blaster 16 ASP, and then a separate Roland Sound Canvas (SCC-1) for General MIDI. I have a PCI / 3D graphics card on it, and then all the other usual upgrades. It runs Windows 98 SE, which I have booting in DOS mode. I use that to play all my older games like System Shock, Ultima Underworld, etc.

[zylon]

Modded my regular play 600xl to 64k and put the 1064 away in its box, also added an SIO2PC unit to my system. I've also upgraded my Dos gaming computer system completely. Now using an old Dell D-3000 with 1.2GB RAM for my Win95 games and older. Using Dosbox 0.74 with great results for my old tandy classics and added WinImage as well for making floppies for use on my original Tandy 1000's.

Love my CGA.

Edited July 12, 2014 by zylon