PDA

View Full Version : Getting interested in the PC Jr.



Corey986
May 7th, 2014, 02:58 AM
So I'm starting to think my first vintage PC, actually my first 1980+ Vintage machine should be a Jr with a chicklet keyboard.

So I have a few questions...

First, is the TV adapter useful at all or must I have a monitor? I like the idea of the "home" computer setup.

Second, is 128k enough? Are there good games/software that run in memory that size?

Third, is there a universal cartridge that you can burn an EPROM of software for the cartridge slot?

Finally, what should I expect to pay for a system in good cosmetic and working condition. I noticed someone selling sealed box 128k systems on eBay, but they seem rather high and I'd still need to find a good chicklet keyboard. I also don't want a bunch of side car expansions adapters. I want a typical home computer setup which would be pretty bones. I like my systems primitive and typical of what a user would really have been able to afford back in the day when a computer was a large chunck of a person's disposable income for the year.

Thanks,
Corey

Great Hierophant
May 7th, 2014, 04:14 AM
1. The TV Adapter is an RF Modulator, so if you want to connect the Jr. to the antenna screw on the back of a TV, use it with a 300 ohm to 75 ohm transformer. Otherwise, you can connect the Jr directly to the TV with the composite video out. If you really want the high end home computer setup, then you should find the PCjr. Color Display or a CGA monitor with the connector adapter.

2. Not in my opinion, 256KB, (one expansion), should be considered the minimum if you want to run DOS games. Cartridge games and PC booters are the best bet for games you can run in 128KB.

3. There was some talk about a universal cartridge over on the IBM PCjr. Support Forum, I'm not sure if it ever matured to a design. Your best bet is to find a cheap cartridge, remove the ROM and install a socket for an EPROM. The Tech Reference can tell you if any of the pins need to be switched.

$100 would be fair, and you should get system, keyboard (the non-chicklet kind) power brick and probably one to two sidecars. The parallel sidecar was fairly ubiquitous.

raifield
May 7th, 2014, 04:56 AM
Most, if not all, of the early Sierra adventure games were programmed with the PCJr in mind, though I have no idea if 128k is enough for them. I know the first King's Quest game had an insert for the chiclet keyboard, not sure about any others.

The PCJr has a pretty iconic monitor, I'd certainly go with that over a television.

Great Hierophant
May 7th, 2014, 05:48 AM
Most, if not all, of the early Sierra adventure games were programmed with the PCJr in mind, though I have no idea if 128k is enough for them. I know the first King's Quest game had an insert for the chiclet keyboard, not sure about any others.

For the booters, yes. For the DOS versions, no, 256KB is required. Only King's Quest I, II, The Black Cauldron and Donald Duck's Playground were released as booters.

Corey986
May 7th, 2014, 05:50 AM
If I did go with a TV, does it only support lower resolutions or does it support all the same resolutions out of the box as the monitor. I do understand that the monitor would be something common in a school setup. But I'm looking for a classic 1983 setup that the "magazines" reviewed with the wireless chicklet keyboard that you could hook up to the living room TV.

I have the perfect 1979 color TV for it which is a little too late in time for my other early to mid 1970's computers.

Thanks,
Corey

Great Hierophant
May 7th, 2014, 06:43 AM
The TV will display the same signal as the "Direct-Drive Video" Monitor and the Composite Color Monitor, but the picture quality will be way too poor for 80-column text through an RF switch. 40 column text and the most frequently used graphics modes for the Jr. (160x200x16 and 320x200x4 and 640x200 artifact color) will be fine.

Maverick1978
May 7th, 2014, 07:37 AM
If I did go with a TV, does it only support lower resolutions or does it support all the same resolutions out of the box as the monitor. I do understand that the monitor would be something common in a school setup. But I'm looking for a classic 1983 setup that the "magazines" reviewed with the wireless chicklet keyboard that you could hook up to the living room TV.

I have the perfect 1979 color TV for it which is a little too late in time for my other early to mid 1970's computers.

Thanks,
Corey
Then get an IBM 5153 CGA with no cords or adapter to actually connect to the PCjr. Most of the PCjr home-based ads that you saw in Magazines sported this setup. Example1 (http://www.brutman.com/PCjr/images/postcard-jr.jpg) Example 2 (http://www.filfre.net/wp-content/uploads/2013/07/home_office.jpg) and Example3 (http://www.brutman.com/PCjr/images/Sampler_front.jpg)

Gawking family with pasted, overly-large smiles not included. PS - note that the last example is the actual disk cover for the PCjr Sampler Disk that came with all PCjr's . They used a 5153 in that as well!

Seriously... if you've room, get a monitor - or use an existing one. You don't want to use the TV as your monitor here. Reading text on a TV, even in 40-column mode, is ridiculous and will spoil the enjoyment of the machine. The PCjr monitor is what was typically seen in schools here. I've never actually seen or heard of a PCjr in the home until I saw Mike Brutman's website - in my experience, if people had a home computer at all, it was a 5150/5160, Tandy 1000, or more rarely, a C64 or Apple II (ie I knew 1 person each that had these)

Eudimorphodon
May 7th, 2014, 09:10 AM
I have the perfect 1979 color TV for it which is a little too late in time for my other early to mid 1970's computers.

Totally off-topic, but out of curiosity what "early 1970's" (1971-1974?) computers do you have that can connect to a TV?

offensive_Jerk
May 7th, 2014, 09:33 AM
I picked up a local PCJR where the guy purchased it new and he had the monitor. I have seen several local for sale with the monitor too. I think the monitor got cheaper after the pcjr was discontinued and probably clearanced out, which is when I assume lots of people bought it.

Corey986
May 7th, 2014, 12:28 PM
Totally off-topic, but out of curiosity what "early 1970's" (1971-1974?) computers do you have that can connect to a TV?

Well for color TVs, I have an Altair Rev 0 (1975) with 1976 Dazzler Card (dazzler is down right now, but I think its the ribbon cable and will fix it on the weekend) and a 1977 Rev 0 Apple II.

For B/W, I have a 1976 Sol20 Northstar setup and a 1978 Sol-20 Helios II setup , a 1976 Apple-1 and I'm always on the lookout for a TV typewriter setup for the 1973/74 Scelbi 8h (right now it's hooked up to a TI Silent 743).

I might use a scopewriter for the Scelbi if Mike Willegal get's one working. If he does, I think a modified 1970's TV set would be super cool.

I really don't have anything from the 80's except a 1980 Rev 4 Apple II and my 1980 TRS80 pocket computer I just got. I don't even own a single C64 or PC. I do have modern stuff like my MacBooks and iPad, but that's about it. I remember the PC Jr articles and as I'm playing with the pocket computer I was remembering the computer scene back in the early 80's. I think I'd also like to get a Sinclair ZX-80, but they seem to be expensive and fragile. I like my machines to work and also to have a limited number of proprietary chips that require sacrificing a whole machine to get another working.

Cheers,
Corey

Great Hierophant
May 7th, 2014, 12:36 PM
I really don't have anything from the 80's except a 1980 Rev 4 Apple II and my 1980 TRS80 pocket computer I just got. I don't even own a single C64 or PC. I do have modern stuff like my MacBooks and iPad, but that's about it. I remember the PC Jr articles and as I'm playing with the pocket computer I was remembering the computer scene back in the early 80's. I think I'd also like to get a Sinclair ZX-80, but they seem to be expensive and fragile. I like my machines to work and also to have a limited number of proprietary chips that require sacrificing a whole machine to get another working.

Cheers,
Corey

The PCjr. has one proprietary chip that cannot be replaced without cannibalizing from another system, and that is the video controller. The rest can be replaced or substituted.

Corey986
May 7th, 2014, 12:55 PM
Does that chip go often? Or is it reliable?

Eudimorphodon
May 7th, 2014, 12:59 PM
Well for color TVs, I have an Altair Rev 0 (1975) with 1976 Dazzler Card...

That's a neat collection of hardware you've got there, for sure. I was just legitimately wondering about the "early 70's" part; short of a Don Lancaster TV typewriter the earliest things I could think of would be in the 1976 ballpark.

(Honestly I can't imagine anyone calling you on using a 1979 TV with your 1977 Apple II, unless said TV is a really forward-looking design. I remember TVs looking pretty much the same from the early-70's though at least the early 80's; if it's wrapped with fake woodgrain you're good to go.) ;)

If it's all about old-school instead of a Jr. you could get yourself a 5150 with a CGA card and use it with an RF modulator; IBM did sell them that way for "home use" although I don't know how many people actually used them like that. (You had to be a bit on the rich side to afford that, if nothing else.) The artifact color tricks some games managed to get out of CGA composite are pretty interesting.

Corey986
May 7th, 2014, 03:08 PM
Oh it would bother me if everything wasn't date correct. I have bought 50 chips to get a single one that is correct. It's kinda my thing. I also am nuts about cosmetic restoration of my systems. I don't call a project done till it looks like it rolled off the factory floor, or at least looks like it did after the owner finally got it working.

I have even tracked down NOS wire for restorations. When I completely rewired my Altair, yes all the 100's of wires involved, I had to buy a giant spool of wire just to get the period correct white wire between the 4 slot motherboards. I even learned to wire lace since my system was laced before I got it, but the wires were brittle with age.

I guess I get it from the car restoration world which was my hobby before vintage computers.

Some of us are just nuts.

Cheers,
Corey

Great Hierophant
May 7th, 2014, 07:25 PM
Do you want a "day one" PCjr.? Early Jr.s would have come with the chicklet keyboard, but after the first few months IBM replaced it with the revised keyboard. Early Jr.s have an internal memory expansion with a metal hood over them and a 33W power supply board. Newer Jr.s have plastic shrouds that go over the rear ports to help support the connectors being plugged in from various devices.

I have never read anything to suggest that the video controller chip had a particularly high failure rate (unlike the chips in the C64), so you are probably safe.

Corey986
May 8th, 2014, 01:30 AM
Your posting is exactly why I started here. Yes, I guess I do want a "day one" PCjr. Is that how they refer to the earlier one, or are there actual "rev #" to the setup?

If anyone reading this post has one of these units, I'd be interested. I'm not up to posting yet in the "wanted" section.

Also any good reads on this kind of detail about the PCjr? I know the system had a short life, but has anyone documented the changes in production anywhere?

Thanks,
Corey

offensive_Jerk
May 8th, 2014, 03:21 AM
Mbrutman has a site with the different models here

http://www.brutman.com/PCjr/pcjr_pictures.html


So this is the kind of setup you want?

http://www.espen.com/graphics/pcjrfamily.jpg

Corey986
May 8th, 2014, 04:27 AM
Exactly the setup and the picture I have in my head that I remember from back then...

Thanks,
Corey