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Tandy 1000 SL gaming issues

C

CarlosTex

Experienced Member
Joined
Mar 26, 2013
Messages
272
So i guess that most people that checks this forum section knows of my Frankentandy Tandy 1000 SL.

Although my overclocking goal is a huge success (surpassing my wildest expectations) i've always had some issues since day 1.

So even before i modded this motherboard i was experiencing some tandy video issues. I was unable to run some games that i tried, most notably:

Red Storm Rising
F-19 Stealth Fighter
Gunship
LHX: Attack Chopper
Chuck Yeager's Air Combat

Among some few others but these caught a lot of my attention as i wanted to play these games on this Tandy.

F-19 Stealth Fighter would launch fine, i could navigate through menus just fine, but selecting "Begin Mission" would end in a black screen.
Red Storm Rising wouldn't even pass the hardware selection screen, crashing as soon as selecting the last option.

For these 2 games the solution was simple but that still leaves me wondering. I had to configure the Tandy BIOS to reserve 64KB of memory for video. After that both games (and some few others) started to run just fine.

Gunship i can't even get to run today. With 64KB reserved for video it doesn't even load the title screen. So by previous experience i now increased the video memory to 128KB and now i could see the title screen with music. But after that all i get is a solid yellow screen. Nothing more, even up to today, mods and all (RAM replaced with newer and faster crystal.

LHX is a slightly different case. I should say that all these games actually run in CGA mode just fine (don't remember if i tried Chuck Yeager yet). LHX and Chuck Yeager both have a minimum 512KB RAM required but need 640KB for something else than CGA in full mode. So if one wants to run LHX with Tandy graphics and only has 512KB RAM left, there is a command line argument SMALL that reportedly uses less RAM.

I tried everything to run LHX getting mixed results. I went as far as running the original copy through the disks, booting from a DOS 2.11 floppy to get as much RAM as possible.

So results with DOS 6.22:

With 64KB memory for video and running "LHX SMALL" i get random colored dots on screen and game crashes.

So i loaded DOSMAX with my lo tech 1MB RAM card and now i could load parts of DOS into the UMB area, but despite getting as much as 575K of RAM i get "not enough memory to run LHX despite having more RAM than before. :confused: Anyway, whenever i load DOSMAX some games have problems, constantly locking up and complaining there's not enough memory available, so i guess the system does not like DOSMAX.


DOS 2.11:

With 64KB reserved to video i now get the same colored dots on the lower bottom of the screen but the game now plays the title screen although it is rolled horizontally and not centered. Game crashes after title screen animation.

With 128KB for video the colored dots have disappeared and the screen is still horizonatlly rolled and off centre but this time the game does not crash and i get to the copy protection screen.


Has anyone been able to run LHX Attack Chopper in a Tandy 1000 SL with 640KB of memory?? I don't fully understand what is going on. I've though about 2 things:

1- I have a bad video controller; - this doesn't seem plausible as it would have to show the same or other issues in diferent games. Heavy games for a Tandy SL like Stunts or 4D Boxing run just fine. Sierra SCI adventures run fine too. Most stuff runs fine actually.

2- I have bad main RAM / video RAM; - this seems not too plausible as this issue was already present BEFORE the overclock and BEFORE all RAM was replaced, but seems to be the best guess considering what i'm getting.

LHX runs fine in CGA of course. So i don't know what to do, i've tried to roll back the system to its original speed and the problem persists, tried the game in 4MHz and the problem persists. It is a bit of coincidence that i would get bad RAM again after i swapped it all but of course it can happen. I have some newer faster RAM coming my way from china that i ordered 2 weeks ago. I'm using HY53C464-80LS DIP RAM, which is 64x4 just as the Tandy requires. I have 70ns versions coming. I'm not too hopeful this will make a difference though.


So i've been reading through tech manuals to see if i forgot something, went through the IRQ 5 jumper change but that didn't make a difference anyway.
By reading the SL tech manual it seems that the buffer blue chip does have the ability to control 768KB of RAM just like the TL and RL:

SL DRAM Control.jpg

SL VIDEO CONFIG.jpg

Unfortunately Tandy/Radio Shack decided not to included all the needed sockets for 768KB of RAM though. I guess that a TL or RL system won't get my issues, although this does not seem to be only because lack of RAM.


I would like to request all Tandy 1000 SL owners to check compatibility with the mentioned games.
 
CarlosTex said:
I would like to request all Tandy 1000 SL owners to check compatibility with the mentioned games.
Click to expand...

I find it highly unlikely that any of my Tandy's would have issues with those games. I'll try some tonight to see if I get anything different.

Here are gunships minimum requirements:

System requirements: IBM-PC/XT/AT/PS2; Tandy 1000/SX/EX, 1200, 3000; 100% IBM compatible; 256K memory; DOS version 2.0 or higher; CGA (4 colors) or EGA (16 colors) or Tandy (16 color) graphics adaptor; joystick is supported but not required.

Here are lhx minimum requirements:

Minimum CPU Class Required, 8088 / 8086. Minimum OS Class Required, DOS 2.0. Minimum RAM Required, 512 KB. Media Type, 3.5" Floppy Disk, 5.25" Floppy Disk

Here are the f19 minimum requirements:

DOS. Business Model, Commercial. Minimum CPU Class Required, 8088 / 8086. Minimum OS Class Required, DOS 2.1. Minimum RAM Required, 384 KB. Media Type, 3.5" Floppy Disk, 5.25" Floppy

----------

Sounds to me like you have a hardware issue with your PC. Likely culprit is memory, but I wouldn't also rule out the processor.
 
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mojorific said:
Sounds to me like you have a hardware issue with your PC. Likely culprit is memory, but I wouldn't also rule out the processor.
Click to expand...

That's what i think too, with the CPU exception. This machine has had 3 different CPU's. I forgot to mention that. The original V30 and both NEC V30HL i own have been put to the test and the problem persists.

So i'm thinking about RAM. This system will get completely new RAM soon, but i'm afraid that even that won't solve the issue which could be a faulty video controller. But why other games show no issues at all?

Just for piece of mind, as i'm writing this i'm trying DOS 3.3 that came with the Tandy 1000 SL. I doubt that will make a difference, but just to rule it out might as well try it.

Problem persists, similar results to when trying DOS 2.11
 
Last edited:
CarlosTex said:
But why other games show no issues at all?
Click to expand...

The video controller could not explain that.
Faulty memory could though. If the memory is high up in the range, it is possible that some games just never use the faulty memory, so only the memory-hungry ones are affected.

I don't think the DOS version should matter much. I ran DOS 5.0 on my 8088 back in the day when I played LHX, and it worked fine, even in EGA/VGA mode, which I assume is as memory-hungry as the Tandy version.
 
Scali said:
The video controller could not explain that.
Faulty memory could though. If the memory is high up in the range, it is possible that some games just never use the faulty memory, so only the memory-hungry ones are affected.
Click to expand...

I agree with that. I tried to swap memory all around but the problem persists. I think i can only solve this when i can try new memory. What worries me though is that i already had this problem with the RAM the motherboard came with, and after i swaped it from memory i cannibalized from VGA cards the problem is still there.

Also that doesn't explain why i can't run Gunship. Gunship does not have high memory requirements, only 384KB if i remember correctly and i also can't run it in Tandy mode although it works fine in CGA.

It was also my understanding that the video controller only requires 64KB of reserved memory for the higher resolution of 640x 200 with 16 colors aka as Tandy Video II. But if i only reserve 32KB for it games like Red Storm Rising and F-19 Stealth Fighter won't work correctly like i described in my first post.

It would be very appreciated if Tandy 1000 SL users could test this games, and check with how many memory reserved for video they have configured in the EEPROM settings.



EDIT: I tried to remove some RAM from the system. No matter what i do i can't configure the system to 512KB, i either get 384KB or 640KB.


EDIT2: Some other games like Bubble Bobble will only work in my system if i have 64KB reserved to video. At 32KB i can't get past the title screen.
 
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You should always reserve 64K, since that's the minimum requirement for any 320x200x16 game that uses two video pages, and it's the requirement for a single page of 640x200x16 which the SL supports.

Short of finding someone else with a 640KB SL, you will need to completely undo your overclocking and enhancements if you're going to get to the bottom of this. You have no baseline.
 
Trixter said:
You should always reserve 64K, since that's the minimum requirement for any 320x200x16 game that uses two video pages, and it's the requirement for a single page of 640x200x16 which the SL supports.
Click to expand...

Thank you, that is a logical explanation for what i've been experiencing. That is perfectly normal then.

Trixter said:
Short of finding someone else with a 640KB SL, you will need to completely undo your overclocking and enhancements if you're going to get to the bottom of this. You have no baseline.
Click to expand...

The FrankenTandy has been running at its default 8 MHz since i started to investigate this issue in detail. The issue persists and i'm 99.9999999999~% sure it has nothing to do with CPU frequency. Like i explained in my first post, this issue was already there when i got the motherboard and no modifications had been done to the motherboard.
 
CarlosTex said:
The FrankenTandy has been running at its default 8 MHz since i started to investigate this issue in detail.
Click to expand...

There is at least one software title that runs on my PC 6300 when it has the 8086 installed, and the exact same software does not run when I swap it out for an NEC V30. Same MHz. Install an 8086 if you want a true baseline.
 
Trixter said:
There is at least one software title that runs on my PC 6300 when it has the 8086 installed, and the exact same software does not run when I swap it out for an NEC V30. Same MHz. Install an 8086 if you want a true baseline.
Click to expand...

I think that with a couple of well documented exceptions pretty much every game works with a NEC V20/V30.

Anyway, there's no need to install an 8086, i found the issue. It was indeed because of a particular enhancement. It seems that the SL is absolutely allergic to any kind of High Density Floppy BIOS. I burned an EEPROM only with XT-IDE and the issues have disappeared, just like that. I can use 2M-XBIOS driver though.

I'm still getting a weird behaviour with Gunship, with a video pattern of "line line black black" screen but that might be just related to game version. Indeed this issue with Gunship was present before any enhancements were applied to the FrankenTandy.
 
Yes, i will do that when i get a chance. Spoiler Alert: it runs very well indeed!
 
CarlosTex said:
Anyway, there's no need to install an 8086, i found the issue. It was indeed because of a particular enhancement. It seems that the SL is absolutely allergic to any kind of High Density Floppy BIOS. I burned an EEPROM only with XT-IDE and the issues have disappeared, just like that. I can use 2M-XBIOS driver though.

I'm still getting a weird behaviour with Gunship, with a video pattern of "line line black black" screen but that might be just related to game version. Indeed this issue with Gunship was present before any enhancements were applied to the FrankenTandy.
Click to expand...

If the XUB in your Lo-tech board is configured to run in "Full operating mode" that could be the reason. See this.
 
PCEM supports Tandy 1000SL/2. May be worth checking out, a positive results at least tells you it's not your hardware. A negative results tells you nothing.
 
Krille said:
If the XUB in your Lo-tech board is configured to run in "Full operating mode" that could be the reason. See this.
Click to expand...

I just checked and it is not running in full operating mode. My issue seems to come from the HD Floppy BIOSes, so far i tried the XT-FDC and Sergey's Floppy BIOS both of which have cause the same issue.
 
I wonder if this is why Ultima V crashes for me with Tandy graphics. It returns "Memory Allocation error: Unable to load command.com, system halted" or something along those lines.

Runs fine in CGA mode.

Also, I recognize that case... :D
 
keenerb said:
I wonder if this is why Ultima V crashes for me with Tandy graphics. It returns "Memory Allocation error: Unable to load command.com, system halted" or something along those lines.

Runs fine in CGA mode.

Also, I recognize that case... :D
Click to expand...

I'll try Ultima V and let you know.


Yep the case is awesome! Cloudschatze, was very kind to offer me a couple of Tandy drive rails, so soon i'll have this thing finished. I'll probably replace the TFX power Supply with a better Seasonic one. I'll recap it and i will have a Tandy to enjoy for a lot of time.

Then i just need the MDA/CGA/EGA FPGA converter and the DOS gaming addiction can begin!

Scali said:
Oooh, that LHX Attack Chopper runs quite nicely!
Click to expand...

Indianapolis 500 runs pretty well too!
 
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