I'm so excited I just received my two CCB boards from Karl and am itching to install them. I was going to install them just as the instructions say soldering the connection wires to the back of the PCB to the specific ULA pins, but then I saw a thread here:
balford wrote: ↑Tue Jun 24, 2014 6:43 pm
Bear in mind you can attach the red and yellow wires to the original 5v and video in points on the PCB, avoiding the need to trail the wires around the PCB
Black can go to the inside of the modulator case.
B
There were a couple of images but none clear enough for me to tell what trace/via/pad (s) the 5v and video IN are to solder the red and yellow wires to. Any help would be greatly appreciated.
So black wire is GND, red is +5V and yellow is video in (ULA pin 16). Brown is video out and the second black is GND again and not needed when out into the modulator case.
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Thanks to you both for your speedy replies! Mark, yes that's what I needed to see. There are three wires coming out of my modulator which look identical. I can find the 5v line easily enough with my meter but how do I know which of the other two is video out? (Besides trial and error )
I was thinking I would clip the wires on the inside of the modulator box and then I could just solder the CCB wires to the existing wire stubs and not have to even put my iron to the zeddy pcb. Is that feasible?
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Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
USA modulator video and +5V connections on an issue 3 board
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USA modulator video and +5V connections on a issue 3 board - close up
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Note that you will either have to move the left hand "video via R31, R32 and D9" wire from the "USA 3" PCB pad to the "video direct from ULA pin 16" "UK 2" pad, or run a seperate new wire to the "UK 2" pad.
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There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
Yes, thanks Mark, the diagrams make sense. I looked at the two zeddys I'm going to install boards into (a TS1000 and a ZX81) and both match your diagram.
I think I'm going to try using the UK2 pad as on mine they're both open vias without solder so adding the CCB board wire will be easier than moving the modulator wire. For the 5V I'll still connect to the original modulator wire inside the modulator case.
For the ground wires is there any reason I couldn't just connect them to the inside of the modulator case? Or is there a better location?
The modulator case is connected to 0V / ground, so yes you can solder a wire to the inside of the case. You do need a powerful soldering iron fitted with a large tip so that you can heat the case up enough. I presume you are removing the circuit board inside the modulator. This should have a ground wire or a soldered ground connection (I have not looked inside a USA modulator yet) that you could use.
Alternatively you could run the ground wire outside and connect it to an convenient 0V pad on the PCB.
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
Yes, I thought I'd take out the circuit board of the original modulator. I can't tell yet how that board is grounded. The modulator case is obviously grounded to the zeddy PCB with two big solder tabs but the only visible connections from the modulator board are the three connections to video and +5v. I'll take pictures along the way to document.
Btw...just for others coming along and reading this thread, PokeMon's instructions and advice are well-heeded. I'm replacing these modulator boards on two zeddys that need to have their keyboard membranes replaced. Trying to replace this from the top of the circuit board with the modulator open and still attached to the keyboard membrane without damaging the membrane is really delicate business. To do this replacement without risking the membrane really requires attaching the CCB to the back of the zeddy PCB per the original instructions.
Since I have to replace the membranes anyway it gives me the opportunity to do it from the front which satisfies my desire to have it all neat and tidy. I can't help myself.
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