beanz wrote:Yes, checked those are right as the one I put in the TS1000 was actually reversed on the board (the red and orange)...so I double checked when I got the the ZX80 one that it wasn't the case on that one. Thanks for all the suggestions...I'm pretty much at the point of either it's the CCB board or something on the ZX80 didn't like me manhandling it. I REALLY hope it's just the CCB board. I'm kicking myself for taking out the modulator innards before testing the CCB board but It's such an easy install I was confident in what I was doing.
Hopefully not a blown 80 but from what I'm told all the logic circuitry for the 80 is still obtainable as is the CPU. The ROM image exists and can be put on a modern EEPROM like the one used in the ZX80 ZXpand conversion so all will end well I'm sure.
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Looking forward to summer later in the year.
Couple of other thing to try - give the pots a "press" from the top and then a quick turning back and forth. I've installed quite a few ZXCCB and did have one or two where I had to do this.
Not a reflection of Pokemons product, probably just me
ZX80, ZX81 - 2C158C Bugged Rom iss.1, 2C158C "kludge fix" iss1, 2C184E iss1, 2C210E iss3, US NTSC iss1 "straight traces", US NTSC iss3 TS1000
Fwapp wrote:Couple of other thing to try - give the pots a "press" from the top and then a quick turning back and forth. I've installed quite a few ZXCCB and did have one or two where I had to do this.
Not a reflection of Pokemons product, probably just me
Ok, I actually thought those pots look like delicate little things. I'll play around with it a bit more this weekend.
I am pretty sure the boards do need a new calibration when using them in a ZX80.
The potentiometers on the board should be adjusted carefully, they do not take much harder treatment.
I must admit that I changed the way the ZXCCB is connected on my ZX80. I changed it so that the input to the modulator is brought out on to a spare finger on the ZX80 edgeconnector (B28 I *think*)
I then installed the zxccb to a bit of veroboard with an edge connector and made a sort of zxccb interface, leaving the ZX80 pretty much untouched.
ZX80, ZX81 - 2C158C Bugged Rom iss.1, 2C158C "kludge fix" iss1, 2C184E iss1, 2C210E iss3, US NTSC iss1 "straight traces", US NTSC iss3 TS1000
Well I tried a new ZXCCB board in the ZX80 and still no luck, I put a ZX81 modulator back on and could "sort" of see something...it would not fully tune in but when I applied power the screen changed and if I pressed a key there was also a change to the pattern on the screen. Again it wouldn't tune in so couldn't see anything as far as Cursor etc.
I measured voltages on each the pins of the ICs that look like memory chips Pin 8 (bottom right if I'm not counting them right) on all of them measured about 5v...however on IC21 it was only 1.5v.
Any thoughts on that? Is that normal for IC21 or should it also be 5v...any other troubleshooting appreciated, I can handle a solder iron but not so much the diagnostics.
Hard to say so far away.
The 2114 RAM chips have 5V at pin 18. Usually pins are marked in anti-clockwise manner, beginning from pin 1 at the lower left corner when you read the name of the IC. Pin 18 is then the top left pin. As far as you get a cursor or something similar and as it moves when you press a key - the ZX80 seems to work in general. There may be an issue with the output video signal. Harder to find without an oscilloscope. You could check if R30/R32 are correct and have connection as schematic. It may be, that the video output is missing and just the sync output here which would result in a picture with a black box cursor (no white K inside) - this maybe hard to find out if not correct tuned in and picture very unsharp.
You may check if pixel data is coming out of the shift register and if the connection A-C or A-B is present. Normally hardcoded on the ZX80. Did it work before ? With which modulator ? There maybe differences between the modulators of ZX80 and ZX81 in video levels.
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