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cbelcher

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About cbelcher

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  1. I did look at the timing data on the Atari side for known resistors and capacitors and played with some best fit curves and the linear equations did quite well over the range. I do have a few boards left over if people are interested.
  2. Searching around non-English language Atari literature, I found a project from around 1990 that sparked some interest. It is a resistance / capacitance meter that runs on the 8bits that interfaces through the joystick port and is based on a 555 timer. I found it here: From AK BRNO Hardwareove doplnky – Mikrocentrum BRNO http://atari8.cz/calp/data/br_man_hw/ Did some Google translating, looked at the schematic and the original pcb and recreated them. Then back to the old days of typing in software - and trying to find errors in the poor text scan. How does it work? Not well... But it is fun. Definitely needs calibration - it is a y=mx+b equation for each the resistance and capacitance - detailed in the documentation. It will never replace your cheapest multimeter, but it does illustrate some interesting hardware hacking. I made a Word document with my poor translation and the original materials, attached. Also there are pictures of the program and my finished PCB and an .ATR below. Atari R-C meter.docx Enjoy! RCMeter.atr
  3. Straight from the BOM and silkscreen - and the frequencies were exactly the same. Values were checked and it looked good from the crystal out through Freddie on the oscilloscope. It seemed like something early since it caused problems for S video composite and the UAV - but I had tried several GTIA, and fixed the CADJ voltage with a 2n3904 transisitor to no avail. But Jurgen said he occasionally sees color issues especially with crystals over oscillators. I changed out to a 4 pin oscillator and it finally worked. Could have been an off-spec component. I doubt it was the soldering as they had all be re-soldered but possibly...
  4. Thanks to Jurgen / tf_hh helping me troubleshoot my lack of color - it came down to the crystal and associated circuit - I removed the crystal and 2 associated capacitors and 2 associated resistors, replaced it with a 4 pin can oscillator and I have color. Now onto more testing and the memory expansion. Thanks everyone for the help, especially Jurgen!
  5. Ok - tried a few more things: Pot reads 500K full scale - and as I said with a new transistor am seeing the full 0-8+ volts at the wipe Yes there is continuity from Freddie pin 37 and GTIA 28 - will see if I can get a scope or frequency counter to tell me the frequency. If not I guess I desolder Freddy from my working 130xe - it's the only chip I have not replaced (it was a new one from Best). I took the entire subcircuit that makes the composite video from luma and chroma out of the video circuit (what the RF modulator did in the original) - in case it was shorting the chroma signal somewhere - lost composite (as expected) but still black and white. Chroma is such a simple 1 transistor amp off of GTIA pin 21 - I may build it on a breadboard and see if it works externally. Glad to take any other suggestions!
  6. Ok I changed Q1 to a 2n3904 and - now I have 8.8V at the color pot - but still have black and white output I changed Q3 (and all the video transistors) to 3904 - and still have black and white I lifted the resistors that connect the UAV section to the board - still have black and white Swapped GTIA and ANTIC with other working ones- no difference Plugged a 130XE into the same power supply, cable, and monitor - and get color from it, but still black and white from the remake board. Looking for other ideas please
  7. Could somebody with a remake board that is working please measure the voltage at pin 17 of the GTIA - or at the wipe leg of the 500K color potentiometer and turn the potentiometer to the extremes and see what range they get? Even simpler would be to measure the voltage on the leg of the color potentiometer closest to the K in the "500K" label - that should be the highest voltage that SAMS labels as 8.5v (I get only 4.6V) I will look into the video amplifier and replace the transistor to see if that helps also. Thank you
  8. So I'm almost done but I'm being frustrated by one last issue - I have a black and white picture... With stock video I have black and white with composite or S video With UAV I have black and white with composite or S video :. I think the issue is very early in the video circuit before it branches to the 2 display circuits - stock and UAV Same cable and monitor on an 800XL and 130XE show color video I have followed the stock schematics the best I can for components between GTIA and the monitor port and have not found any issues. Made sure Pin17 of GTIA actually connected to the socket and the board Swapped GTIA without improvement Swapped the 4050 without improvement Read the SAMS guide for the 130XE and they say pin 17 of GTIA should vary from 0-8.5V with adjustment of the color pot - I only get 0-4.5V - soooo maybe? Looking at the board it looks like the area around Q1 is where this voltage comes from - but I don't think it's a boost circuit - no coils... (Sorry not an EE) Could you guys verify that 8.5v is generated there for GTIA pin 17 / CADJ? If so - anyone see my error, or should I just replace Q1? Or maybe I am way off and would appreciate help to get in the right direction!
  9. Yep - did something similar with Mr. Robot's case. Used some short leads to make the connections to a dip switch which is epoxied to the case.
  10. Funny I looked at this thread and noted the cheesy cases they reused for this - I went looking because I picked up a couple of similar enclosures and assumed they were from some old pong clone system... Aaaaand - I found that one I picked up was a Parrot without the label! (The other two I'm convinced are old pong controllers that must have connected via an RCA cable) To fill in the schematic above: Yes, they are pins 7 and 9 My transistor is a kn2222
  11. Ah - I was confused by that. I thought the new update via SD made it possible to update older PlusCart Duos. So - ONCE updated to 102.3.1 - we will be able to use the SD card for FUTURE updates?
  12. I have a PlusCart at 2.1.0 firmware. I renamed the 102.3.1 to firmware.bin and put it on the root of the card Started up and got the orange highlighted option "SD card firmware update" Selected it and had the spinning plus sign for 45 min before I gave up and rebooted. Still at 2.1.0 Anyone been successful?
  13. Could you point me to your fork please?
  14. cbelcher

    Movie Cart

    Yes - it needed Reset. Thank you
  15. cbelcher

    Movie Cart

    Thanks for the new hex file - I got that burned to the PIC. And block_writer.cpp compiled easily enough under windows. But trying to encode various m4v files with colorize.toe it always stops at 30 seconds... Both on my Windows box and Mac - with the most recent downloads. I thought it might be an issue with the TouchDesigner license / key but it looks like a have a valid non-commercial one there. Any ideas? Thanks!
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