800XL with several bad ICs

[800XL with several bad ICs]

I will check the sockets. I am using a white brick power supply that gets checked just about every time I work on a computer; if not directly, then indirectly because one of my checks is to verify voltages through the connector, the switch, and caps near the switch.

[800XL with several bad ICs]

Yesterday I was troubleshooting an 800XL MB that gives nothing but a black screen. While I was checking memory chips, my test board suddenly went the way of the bad MB and gave nothing but a black screen even with its original supposedly good chip set.  Today when I turned it on I still got the black screen but it was making a noise like a screeching sound.  It will boot Star Raiders but nothing else and it still makes the screeching sound mixed with the sound that Star Raiders usually makes.  I tried swapping our the ROM and BASIC but I haven't had time to recheck all of the ICs.  What besides the ICs would be a good thing to check.

[New Atari 600XL owner!]

11 hours ago, BillC said:

I prefer whats called a brad-point drill bit, it's like a cross between a spade and regular drill bit.

It's only for soft material like the spade bit, the point keeps it centered while the 2 outside cutters do the work.

I drew a circle on the case and then used a dremel tool and successively larger grinding wheels to make the hole.

[New Atari 600XL owner!]

On 12/30/2019 at 5:19 AM, xrbrevin said:

here is my 64k mod:

 

here is my 600XL UAV - with explanation

 

due to height of the components surrounding the 4050 chip, i decided to relocate the UAV board as shown in the image. to do so, i had to run link wires instead of the usual direct method.

the bottom 2 wires are DC +/-

the group of 5 wires above that are the input signals from the 4050 chip to the UAV

the top 4 wires are the display output signal to the display port 5-pin DIN

 

the guidance material i used is here:

UAV.zip 4.5 MB · 10 downloads

 

but i also got v.good support from user: @Bryan who i bought it off

If you push all of the resistors and capacitors to the left or to the right about 45 degrees you can fit the UAV in and it will still fit under the shield.

[Idea:External Atari ST drive transformed to 8-bit (XF551 internals)]

Thanks, I will check both ways, voltage and frequency.

[Idea:External Atari ST drive transformed to 8-bit (XF551 internals)]

I think the oscillators may be bad on the last two boards that I populated.  I have a multimeter with a frequency tester and I don't get 8.0 when I check the pins but I am not sure if I am checking them correctly.  I have tested the meter on the 2 pin crystals on a 800XL board and I get the correct reading.  I am not sure which pins I check on the 4 pin crystals on the 314/354 boards.  Can anyone enlighten me?  I have googled and did not find any info about testing 4 pin crystals.

[New Atari 600XL owner!]

I just finished installing a UAV-D and the video is really clear.  I had tried to do a SuperVideo 2.1 but I couldn't get a picture after I had installed all of the components.  Everything is so confined in the 600XL that I could have made any one of many soldering mistakes so I would rather install a UAV than try and find the error(s).  Where can I find information on the RAM upgrade? One other thing that is puzzling is that I can't get my Sdrive to work with the 600XL.  Is there something that makes the Sdrive incompatible with the 600XL?

[UAV in 600XL?]

I have tried to do SV 2.1 mods on two different 600XLs and was not successful so I just installed a UAV in each one and got a pretty good video.

[Idea:External Atari ST drive transformed to 8-bit (XF551 internals)]

I struck out with another 551/314 PCB. If there is anyone out there that is really good and confident about populating a 551 PCB, I would be willing to trade some materials for a finished board. I send you two PCBs, all of the parts required to populate the PCB, a working 3.5 drive and a SF354 case. Then when you finish, you just send me one of the PCBs

[The UAV Rev. D Video Upgrade Thread]

7 hours ago, rmzalbar said:

Does anyone know if the Super Video 2.1 modifications for 800XL and 1200XL will interfere with a new UAV installation? Should these modifications be reversed first?

The SV 2.1 does not interfere with the UAV. The UAV bypasses all of the SV2.1 circuitry.  I am pretty certain that this is true because I did a SV 2.1 on a 600XL and totally screwed it up, I wasn't able to get any video at all and rather than try to find my mistakes I just installed a UAV-D and the video was great.

[Idea:External Atari ST drive transformed to 8-bit (XF551 internals)]

I now converted a SF314 drive to 8-Bit use.  This was extremely simple once I was finally able to put together a working PCB. Just insert the PCB in the case and connect the cables. Works nicely.  I have considered having a new model label made and label it as an XF315A or XF315M, but I don't know if that would be legal if I decided to sell one. 

[Idea:External Atari ST drive transformed to 8-bit (XF551 internals)]

21 hours ago, Kyle22 said:

Is there anyone who makes an SIO cable for this? I like it very much, but I can't see well enough anymore to solder DIN connectors.

 

I have always wanted a drive like this!

 

That is a beautiful drive.

 

I have made 4 or 5 SIO cables.  I have to use a lighted magnifying glass to do most of my soldering.  I wish I could afford one of those magnifying glasses like dentists use.

[Idea:External Atari ST drive transformed to 8-bit (XF551 internals)]

I am having mixed success with assembling a working PCB. I don't know if it is due to salvaged parts, or poor soldering skills but my success rate is about 50%.

[Atari 80 column software/hardware]

On 4/21/2019 at 10:26 PM, hueyjones70 said:

I can't figure out what I am doing wrong with the Atariwriter+80. I have downloaded the zipped file, extracted the ATR, saved it to a micro card for the Sdrive, when I attempt to load the file the computer makes two of the clicking noises that indicate loading a disk then nothing. I have downloaded several other programs using the same process and on the same card that work flawlessly. I have tried on a 130XE and an 800XL with the same results. Any suggestions, is there another source besides the one in this forum (post#37). I know that others say they have successfully run the program on real hardware and Both of my computers will run the program from an actual disk drive but the ATR is giving me no joy.

I have discovered that my inability to run the Atariwriter+80 on the Sdrive2 was because of some fault with the Sdrive2, probably associated with reading double density files. I finally tried the program on another type of Sdrive and it worked correctly.

[800XLs for sale]

14 hours ago, OLD CS1 said:

For the non Atari-inclined (like myself, who owns an 800XL and a 130XE but does not know the lingo,) could I impose upon you to explain the upgrades and what they do?

The SuperVideo 2.1 changes some resistors and capacitors in order to separate the Luma (black&white) signal from the Chroma(color) signal so that you don'd get colored objects bleeding into each other.  It also sharpens the pixel definition.  The UAV (Ultimate Atari Video) does this with an add-on board that is plugged in to the motherboard.  The Wiztronic and Rambo upgrades increase the RAM from 64K to 256K.  

[ATR Downloads]

I tried the files and one of them has DOS 2.5 built in as the boot file. When I loaded the file I got a ready prompt so I had to load DOS then use the L command and load LW.EXE.

[800XLs for sale]

I like to buy 800XLs, upgrade them and resell them for a small profit. I can do video upgrades (usually SV 2.1), install UAV, install memory upgrades, (Wiztronics or Rambo), and generally clean them up. I usually sell on eBay but I would be willing to do business with forum members without the fees associated with eBay. Anyone interested can message me and work out details.

[ATR Downloads]

1 hour ago, DrVenkman said:

https://atari8.co.uk/the-last-word/

I know that this program requires a DOS, how do I load it from a disk emulator like an Sdrive?

[ATR Downloads]

Where can I find atr files to download other than Atari Mania.  I am especially interested in Last Word

[Atari 800XL Memory Problem]

I finally figured out what was wrong, I had installed xx256 memory chips so I could do a Wiztronics memory upgrade and one of the chips was bad.

[Atari 800XL Memory Problem]

I have switched out the large chips and the MMU and the problem persists.  Sometimes when I boot I don't get any noise and sometimes I don't get a ready prompt and on those occasions the computer doesn't respond to any commands.

[Atari 800XL Memory Problem]

I tried with an original ROM and one of the dual OS EPROMS. Same results. When I got in with BYE the keys all worked OK for a few tries. I am going to switch out the GTIA and maybe the PIA if nothing shows up there I will run the SALT diagnostic.

[Atari 800XL Memory Problem]

GTIA should be easy to check, ribbon socket cable also.  

[Atari 800XL Memory Problem]

I don't think the problem is with the keyboard, I used two different keyboards with similar results. Also, sometimes when I press the OPTION key I get random letters and characters displayed on the screen.

[Atari 800XL Memory Problem]

It is obvious that I should should check out my OPTIONs.