josephs@ttidca.UUCP (04/02/87)
I've just about decided to add a color capability to by AT&T 6300. The two alternatives which come to mind are 1) replacing the mono- chrome monitor with a TAXAN 630 (which I've seen advertised at 'bar- gain basement' prices) or 2) disabling the video controller chip and acquiring an EGA card/monitor. The common attribute shared by these two alternatives is that either would give me a current color capabil- ity. However, the TAXAN is only good on my current system not upward compatible as would be an EGA combo. Question: would an EGA monitor, particular one of the multi sync ver- sions (like the NEC), be compatible with the current video controller and obviate the need for the TAXAN while giving me an upward compati- ble expansion path? Would I need someone to cut me a cable and, if so, what would be the pin assignments. Thanks in advance -- I'll summarize any responses I get. Bill Josephs (213) 450-9111 Citicorp/TTI 3100 Ocean Park Blvd. Santa Monica, Ca. 90405
wtm@neoucom.UUCP (04/06/87)
I think the off the shelf monitor you'd want for the AT&T 6300 is the Taxan-640. The model 640 does the double-scanned video that is put out by the 6300. The colors in text are very nice and the characters are very shrap (I've been using a 640 for a while). Of course, you still "only" get CGA and 2-color 640*400 graphics. Getting an EGA card can be a little more problematic if you have an older 6300. The newer 6300s with ROM Diagnostics 1.43 can readily accept an EGA card. Just make sure the two vertically oriented jumpers (there are also two horizonal jumpers) are on their bottom two pins. It should find the EGA card without any problems. We've used a Paradise PEGA-II autoswitch card without incident. Seems like a saw a very competitively priced deal that bundled an autoswitch card with a Taxan 760 (which is a pretty good non-multisync monitor); check computer shopper. Oh yes, I was talking about the jumpers on the indigenous video card. On older 6300s, you have to do a minor hardware mod to disable the indigenous video board. That's been described on the net. I'll let somebody from AT&T answer that question. --Bill (wtm@neoucom.UUCP)
wtm@neoucom.UUCP (04/07/87)
I intended to mention in my previous article, Re: the Taxan model 640, that the 640 is relatively sensitive to RF. Running on the AT&T 6300, I occasionally have trouble in the graphics modes with the monitor apparently loosing horizonal hold in a few isolated portions of the screen. Placing my hand near the monitor or repositioning the monitor signal cord will usually make the problem go away. I determined that the the vendor-supplied cable for the AT&T computer's db-25 (as opposed to the more normal db-9) connector does not carry the frame shield through from the computer to the monitor. This allows the monitor chassis to pick up RF. To put an end to the problem, I added a ground strap from one of the screws on the 6300's case to a screw on the Taxan's case. I talked to Hitton Patel, the video Engineer at Taxan, and he claimed that the vendor-supplied cable was the culprit. He sent me a replacement cable; alas it has a db-9 on the end -- but it does carry the shield through. It's curious that the noise problem is peculiar to the 6300's graphics screen. I'm not sure who makes the Taxan 640; the newer models' guts are made by JVC for Taxan. --Bill Mayhew (wtm@neoucom.UUCP)