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The FrankenTandy 1000 SL: fastest XT in the world?

soviet9922 said:
yes i'm reading the thread see the picture but is hard to tell what you ended up using to reach the 14 mhz.

I see you when back and fort and then removed the patch and then added it again and replaced the ram.
Don't whan't to take your time Carlos but can you elaborate on what is the final modification required to reach this speed ?.
Also what oscillator you used externally a can one and what speed how you wired it up ?
Click to expand...

Basically you take your OSCI socket and solder wires to the oscillator of the motherboard, the 24MHz one i mean. You only need to solder 3 wires. One to GND, other to the VCC which is 5V and the output pin from the socket you splice and solder it to the trace that leads to R24. At this point you already spliced the trace that takes the 24MHz signal to the R24 resistor that leads to the OSCIN pin on the buffer blue chip. So now you can put whatever OSCI you want on the socket.

Remember that the buffer blue chip is gonna divide by 3 to get the CPUCLK. So to get 14MHz you need a 42MHz OSCI. It's the same type of oscillator that is used on the motherboard, a rectangular 5V TTL oscillator. Crystals need their own circuit, Oscillators don't.
 
I managed to find a 50MHz oscillator:

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Updated results at 16.6Mhz:

TOPBENCH reports that my system is:


2.36x faster than the original IBM AT,
2.00x faster than the 8MHz AT,
1.44x faster than the IBM 5162,
1.73x faster than a Tandy 1000 TL/TX,
1.24x faster than the SEGA TeraDrive,
1.53x faster than IBM PS/1 Model 2011,
1.18x faster than a Compaq DeskPro 286.


This really makes me think on how much crippled the IBM AT's and the Tandy 1000 TL are crippled compared to other well tuned 286 systems. The IBM XT-286 only runs a 286 at 6MHz and it performs in line with what a good 286 system should do. My 16.6MHz V30 is only 44% faster against the 6MHz XT-286 while i'm 100% faster than the 8MHz AT. AT's are the suck
 
The XT-286 performed well because of the zero wait state RAM.

It's important to remember that clock speed is only one variable in a system. It's not just AT's that were crippled; consider the 386SX which due to its cut-down nature usually performs around half as well as a 386DX.
 
Wow.. I totally forgot about Codename ICEMAN. I played that a long time ago.. I think.. wow... like, completely forgot about it.

I didn't realize you could run an 8088 at 14mhz without burning it out.. pretty awesome!
 
falter said:
Wow.. I totally forgot about Codename ICEMAN. I played that a long time ago.. I think.. wow... like, completely forgot about it.
Click to expand...

It has pretty good music for the IBM Music Feature Card :)

falter said:
I didn't realize you could run an 8088 at 14mhz without burning it out.. pretty awesome!
Click to expand...

It's not an 8088 machine. It was originally an 8086 machine, but the CPU is replaced with an NEC V30HL, which is designed to run at higher clockspeeds. The trick is getting the rest of the system to work at the different clock.
 
falter said:
I didn't realize you could run an 8088 at 14mhz without burning it out.. pretty awesome!
Click to expand...

It's a NEC V30HL, which is an improved 8086 not only capable of reaching higher clock speeds it can also perform faster clock per clock than a 8086.

It also includes some of the newer instructions that debuted with the 286. This makes the V30HL capable of running software that won't run on a 8088/8086.

The system is now running at 16.6Mhz.

BTW, i just learned about the Olivetti quaderno pt xt 20, which uses a NEC V30HL at 16MHz. I have a feeling that my system is still faster, and i have yet to try it at 18MHz.

One thing for sure, i'm getting close to its limits.
 
CarlosTex said:
Basically you take your OSCI socket and solder wires to the oscillator of the motherboard, the 24MHz one i mean. You only need to solder 3 wires. One to GND, other to the VCC which is 5V and the output pin from the socket you splice and solder it to the trace that leads to R24. At this point you already spliced the trace that takes the 24MHz signal to the R24 resistor that leads to the OSCIN pin on the buffer blue chip. So now you can put whatever OSCI you want on the socket.

Remember that the buffer blue chip is gonna divide by 3 to get the CPUCLK. So to get 14MHz you need a 42MHz OSCI. It's the same type of oscillator that is used on the motherboard, a rectangular 5V TTL oscillator. Crystals need their own circuit, Oscillators don't.
Click to expand...

Thanks for the info ordered from ebay a can 50 mhz OSCI.
Have to dig in my spares maybe ii have some, my TL already have a 16 mhz V30, do you added a heat sink to it ?, how hot is running ?.
 
soviet9922 said:
Thanks for the info ordered from ebay a can 50 mhz OSCI.
Have to dig in my spares maybe ii have some, my TL already have a 16 mhz V30, do you added a heat sink to it ?, how hot is running ?.
Click to expand...

Surely you mean your SL. No, i did not put an heatsink, the HL is rated for 16MHz it won't need one.
 
soviet9922 said:
Yes mean the SL, this overclocking thing is cool they are a lot of games that use nice tandy graphics and sound that crawls on a plain 8086
Click to expand...

That was the whole point for me to bring the system up to the max.

The SL has something though that really sucks. Unlike the TL and RL machines you cannot install the 768K which allows you to have the full 640K memory. On the Tandy 1000 SL the video is gonna always steal you conventional memory. I recommend at least a minimum of 64KB for the video, otherwise some games will stop working. Some Microprose games and others don't work with Tandy video with only 32K.

I actually installed a lotech 1MB card for UMBS, but using DOSMAX to load DOS in the UMA does not go well with the system. Some other software will stop working too.

So i guess the Tandy 1000 TL is the best 1000 of them all, but this is all subject to criticism of couse.
 
Your frankentandy not withstanding, I've felt that the Tandy 1000 TL/3 (which I've never seen) is the best Tandy. You get all of the Tandy-specific features at default ports, the extra 128KB for video RAM, and it sports a 10MHz 286. My personal runner-up is the Tandy 1000 TX, since it's essentially a Tandy 1000 on steroids (and also has the extra 128K for VRAM).
 
Cant you pop in the EGA/CGA card and solve the Ram problem in the SX/SL?s
 
Not considering any modifications, and not having the luxury of upgrading these machines the way we do now, then yes, i agree the Tandy 1000 TL/3 was the best of them all.

Somehow the TL machines, at least by comparing with what's available on TOPBENCH Database, seem like really crippled as far as performance. I don't have a TL to tune, but from TOPBENCH the score is underwhelming for an 8MHz 286. I'm used to well tuned AT clones.

I imagine that a well tuned TL with no RAM wait states could potentially produce nicer results.

A similar mod i did with my SL on a TL would potentially make a Tandy 1000 to rival fast 286 EGA configurations.

The RL is nice and compact, but it was not a good option for me considering i live in Europe and i needed to also mod the PSU for 220V juice. Also there's little expandibility in the RL and the CPU is PLCC and socketed.

With a lot of elbow grease one could desolder the PLCC CPU and solder 40 wires from a 40 pin DIP socket to the corresponding pads on the motherboard and upgrade the CPU to a V30. But this would not look pretty.
 
Trixter said:
Your frankentandy not withstanding, I've felt that the Tandy 1000 TL/3 (which I've never seen) is the best Tandy. You get all of the Tandy-specific features at default ports, the extra 128KB for video RAM, and it sports a 10MHz 286. My personal runner-up is the Tandy 1000 TX, since it's essentially a Tandy 1000 on steroids (and also has the extra 128K for VRAM).
Click to expand...

Don't leave the RLX out. It's the best pizza box ever, has all the advantages of the TL/3 except only one ISA port, but it has a "real" parallel port/PS2 mouse/etc.
 
keenerb said:
Don't leave the RLX out. It's the best pizza box ever, has all the advantages of the TL/3 except only one ISA port, but it has a "real" parallel port/PS2 mouse/etc.
Click to expand...

But it has onboard VGA, so that prevents it from running older DOS games to their full ability -- many don't give you Tandy 3-voice sound unless you also have the special Tandy/PCjr CGA graphics. And it has the typically imperfect VGA emulation of plain CGA graphics.

Radio Shack also loved to bundle the 1000RLX with the absolute worst color VGA monitors ever known to mankind, with a horrendously grainy 0.52 mm dot pitch and no anti-glare coating on the CRT.
 
I have to agree with vwestlife here. There was no point for me to get a VGA Tandy system, i got a tandy for its Graphics/Sound abilities on their default ports. And of course the extra speed with the overclocking makes the machine much more enjoyable. If i de turbo it, i can still get its original speed anyway.

On another note: I disabled all the ports of my SL, including serial, parallel, and floppy controller. This way i can use a 16bit floppy controller on this system in conjuction with HD floppy extensions glued to the XT-IDE BIOS, thus i have ability also to use the standard serial, parallel and even joystick ports.
 
Could this same mod be performed on a 1000hx? I have wondered about switching out the oscillator to run a V20hl at 16mhz.
 
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