Showing off my Quadram Datavue 25

[Coder]

Another eBay find. I really just need to delete my account there. I have zero self control, apparently. This is by far the most fragile computer in my collection. You even think about putting pressure on it's sun-burnt plastic case and it'll snap. I had pieces breaking as I tried to move them slightly to super glue other pieces to them! But, it's finally functional and in mostly one piece. It's a neat little machine. I was told it's gas-plasma, but I don't think so. The front surface is more plastic-y like an LCD. All of my other gas-plasmas are glass. That and the top half has to "warm up" to maximum brightness and is quite dim when powered on cold. I think it has two CFLs and the top is dying.

The computer boots up to a screen where you can allocate some of the memory to use as a RAM disk. That was more useful on the earlier models, as they lacked a HDD. Mine has a 20MB Epson MFM half-height drive, so the RAM disk is less useful. What is useful, however, is the built in "teach" function. CTRL-SHIFT+T gives you the DIP switch settings and a list of other keyboard shortcuts for things like changing the screen brightness and contrast, and accessing it's built in dumb terminal mode.



It's standout feature is it's wireless keyboard. It's actually quite nice. The keys are mechanical and have great feedback. Very tactile. The infrared wireless works surprisingly well. I worried it would be laggy, but I haven't noticed any, if there is. It does need to be line-of-site, but you can be at pretty severe angles as long as there's no obstructions in the way. The keyboard can be wired, if you have the proprietary cord. But from what I hear, even corded, the keyboard needs it's 4 AA batteries to work.


RAM is expandable via a couple of small daughter boards that are accessible from a small panel on the top, left hand side of the machine. The bottom one is populated and the top one has sockets that can be filled. The currently installed RAM needs to be set via the DIP switches, also contained inside this panel. The lower panel was for expansion, though I haven't heard of any expansion cards being offered. I don't know if this is a simple ISA connection or if it's more proprietary. I have detailed pictures of the motherboard if anyone wants to try to figure that out. Also of note on this side is the A/C power input. Notice the small square plate to the lower left of the A/C connector? On older models, that was a button to eject the A/C power adapter to install a battery instead! My model is A/C only and has a permanently installed power board.



On the right side of the machine is are the 3.5" floppy drive (720kb, as far as I can tell) and 20MB HDD drive. Also on this side is the reset switch and a DC power input. I think the DC input is a leftover from when you could have had this battery powered. It's interesting that the left it in. I have no idea if it's functional.

Sadly the HDD in mine is dying. I'm looking for a good way to back it up before trying to play with it too much more. There's not much on it, but I'd like to keep it for posterity. I've been looking at HDD replacement options. The MFM controller is on a daughter board (right hand picture above) connected to the motherboard via ribbon and I believe uses the SASI interface. My understanding is SASI was the precursor to SCSI and is mostly compatible. That makes me wonder if a SCSI drive or SCSI to flash adapter may work.

 

[Eudimorphodon]

That and the top half has to "warm up" to maximum brightness and is quite dim when powered on cold. I think it has two CFLs and the top is dying.

That yellow color makes me suspect it’s electroluminescent, not CFL. Those were pretty common before color LCDs. (When suddenly it became important that the backlight be white.)

 

[Coder]

On the back of the unit, there's a healthy array of ports. From left to right: power switch, 25 pin parallel port, 25 pin LPT printer port, DB9 RGB video port, and composite video out. Additionally, there are two covered ports, one for an external floppy and the other for expansion. Datavue offered a 5.25" external floppy drive that clipped on to the back of the computer. The pinout is standard floppy, but power for the drive is supplied on some of the pins. I haven't mapped out which ones, but there are 4 pins that go off separate from the rest and connect to the main daughter board for what I assume is power.



Inside the machine, the we can see how the motherboard and the main daughter board fit together in a T configuration. It's very difficult to attach and separate without damaging things! The CPU is an OKI M80C88 and there's a socket for a math co-processor. Notice on the left side of the motherboard are two 34 pin headers marked CN2 and CN3. Both are populated on the back of the board. CN2 is used for the internal 3.5" floppy and also for the external floppy port on the back of the machine. CN3 is unpopulated. I believe this is for an additional 2 floppy drives. Both the user manual and the built in "teach" function mention DIP switch settings for 2 or 4 floppy drives. They mention 4 as being "not implemented". So it may be possible to add a GoTek or other floppy based device in the expansion port and just plug it in to CN3 while still retaining the original 3.5" drive and external port. I'll also point out that they use the same sort of "number/letter quadrant" silk screening on the edge of the boards like apple did.



If you're thinking that the second floppy header is for the expansion bay, it's not. There's a separate 34 pin header on the main daughter board (shown above) labeled CN11 that the expansion bay edge connector plugs into. Speaking of the expansion bay... It's proximity to, and shared pins with, CN10 make me wonder if it's a cut-down ISA bus. CN10 is the "EXT BUS" external bus port on the back of the machine. I don't know for sure that its ISA, but it is 62 pins, so it seems likely. Who knows if the pinout is standard though.

Other things of note on the daughter board:

• It appears to have a separate speaker and buzzer. I don't know if this is common or not. At least I assume that's a buzzer labeled "BZ" in the top right corner.
• The VARTA 2.4V battery hasn't leaked! It's a 3 pin "SafeTronic" 2.4v 100mAh NiCd. It currently reads 1.4v and isn't leaking. I'm looking at replacements. It's a 3 pin battery, but from what I can gather, 2 of the pins are on the + side of the battery.
• CN12, the 6 pin on the top left near CN10 and CN11 goes to the external floppy port. I think these are for power. They get added to the standard floppy ribbon, but only for the external connector.

Here's the two floppy headers on the back of the motherboard. The bottom one is used by the internal floppy and the external floppy port. The top is unused. Next to the top floppy is the connector for the RAM daughter boards. Below that is the two banks of DIP switches. The function of these can be shown on-screen by pressing LCTRL+LSHIFT+T at the boot screen. It think it will come up even after booting. But definitely while booting. Below that are the two ROM chips. On the opposite side they are labeled as the top being the BIOS ROM and the bottom being BASIC ROM. I haven't read anything about it having a built in BASIC compiler, but maybe?

 

[Coder]

That yellow color makes me suspect it’s electroluminescent, not CFL. Those were pretty common before color LCDs. (When suddenly it became important that the backlight be white.)

You know, I almost said electroluminescent, but I didn't know if EL would dim on one half like that. I don't don't much about EL backlights. I have a couple other portables with EL backlights and it definitely "feels" more like it's EL. Info on this model was very hard to come by. The only manual I could find doesn't even mention the option of a hard drive or other screen options.

 

[Eudimorphodon]

You know, I almost said electroluminescent, but I didn't know if EL would dim on one half like that.

It may well be composed of several strips of EL material instead of one big panel. If you were going to try to repair it I’d probably guess its a problem with the inverter instead of the panel itself.