dafa_123

Did the test, here are the results: U5:[email protected] U5:[email protected] U6:[email protected] U6:[email protected] U6:[email protected] U5 tested low @0.1v when tested following the diagram. U6 appears in the wrong order. I got: G G 5 low on pin 11 instead of 14 @0.1v G 5 5 low on pin 9 instead of 12 @0.1v 5 G G low on pin 14 instead of 11 @0.1v 5 5 G low on pin 12 instead of 9 @0.1v The rest are according to the diagram and I get a low @0.1v

I was so tired, I did not noticed the trigger level. I adjusted it and took a new reading. Still does not look Ok. I might not be using the oscilloscope correctly, I am not an expert. Yes I have the CPU on a socket. Do you have a procedure that could tell me which lines to test and what to expect? Thank you

I fixed the traces issues with U2. I am now buzzing everywhere that I should but still get the same symptoms. Most of my Hantek oscilloscope reading don't show what they should according to the repair manual. I am getting a weird signal from U1:6. Could the clock crystal be bad? Not sure what to look for next. I've replaced the ram and BIOS with the Console5 Upgrade kit, replaced the CPU and GPU and I get the exact same issue. Double checked and repaired all traces according to the diagrams you provided. I get proper voltage on all chips that I check. Unless the issue is with one of the SN74xxx chip, not sure what to look for next.

I connected U6:1 to U8:3 tested the traces. Same issue, all the traces buzz as they should. Just not sure with the new BIOS. If I compare the old BIOS connections with the new one, U2:22 and U2:20 are now connected. W4 and W5 are connected together. Not sure if I should be buzzing between W4 and W5. There might be some wrong here. Now I get U1:1 connected to U2:20, U2:22 and U2:23. Is that normal ?

I've been going through the all the traces with my meter. I have pretty much repaired, tested and verified all the traces from the Video Controller and Video DRAM diagram. I have a few questions regarding the Processor, Program Memory and BIOS diagram: 1. WJ4 and WJ5 do not appear to be jumped on your diagram. Is it because it's the diagram with the original BIOS? If that is the case, do you have by any chance a diagram with the Console5 BIOS upgrade? 2. Should U1:6 be connected to U8:3? 3. U8:3 does not buzz either with Expansion slot 45(44)? 4. U1:6 and Expansion slot 45(44) buzz. Should I put a jumper between U1:6 and U8:3? All other traces from the Processor, Program Memory and BIOS diagram seems to be connected properly. Could it be just a bad clock connection issue? BTW, thank you for the files

I may have a bigger issue with this board. I solder the missing connection and now all the meter test I do works. I checked pretty much all the paths on between U1, U2, U3, U4, U5 and U6 and they all appear Ok. I now get a signal on U2:22 and I get a dip on the 5v of U3 and U4. I started checking the lines between U1 the memory and none of the lines appear to be connected, see attached diagram. Even between memory chips some lines don't work. If that is the case, I will have to solder jumper cables between all the chips and CPU. I am starting to wonder if it is worth the effort? Any thoughts? Thanks.

Didn't you alter the board as required to install the new ROM chip? Yes, I followed the instructions step by step from the site. As for the data lines, what is the resistance? I don't have any resistance. I only have a number when I put the meter in Diode mode. Since I replaced the CPU and I am now using a socket, the contact with the pins should be good. I can try re solder the problematic pins. If that doesn't work, should I jump the pins with a wire in order to make sure that the connection works? Thanks

Since the CPU does not seem to be getting any useful DATA, I checked the traces using the diagram I attached to this post. Following the diagram and using my multi meter in Diode mode so that I can hear a buzz when the traces are connected, I found some that do not buzz pin to pin and should be connected according to the diagram. I do get a value on the multi meter but no buzz. My question is, should I solder a jumper cable between those points? The BIOS is the one I installed from Console5. U2:Q1 pin 12 is not buzzing to U10:D1 pin 15 U2:Q3 pin 15 is not buzzing to U10:D3 pin 8 U2:Q6 pin 18 is not buzzing to U10:D6 pin 10 U2:Q7 pin 19 is not buzzing to U10:D7 pin 13 Pin 20 is not buzzing to WJ5:2 All the rest buzz when I test pin to pin. I checked from U2 I get a buzz on those pin with U3 and U4.

I am going nuts with this console. I keep getting inconsistent readings. I took new readings with the Hantek Oscilloscope and I get some weird output. I don't know if this can give us a clue but I often need to flip the switch on/off several time before I actually get a signal other than a flat line. Ok so here it is: U1:6 --> The clock signal I see does not appear to be valid. U1:16 --> Can't seem to see any interrupt. U1:17 --> This one is a flat line. U1:18 --> Also a flat line. U1:19 --> I get a signal, but it's not like the one in the repair manual. U1:22 --> Flat line. U1:24 --> Again I get a signal, but it's not like the one in the repair manual. U1:27 --> Appears almost normal. U1:28 --> Also appears almost normal. U1:35 --> I seem to getting a pulse. U6:5 and U6:5B --> I get a bunch of out of spec signals and after a few seconds nothing else. U7:3 --> I seem to getting a proper signal. U8:1 --> Seems normal. U8:3 --> Clock does not appear normal. U8:8 --> Clock does not appear normal. U8:9 --> Clock does not appear normal. U9:1 --> Signal does not appear normal. U9:2 --> Signal does not appear normal. U9:3 --> Flat line. The address line could be dead. How can I fix this? U9:17 --> Signal appears similar to the image in the manual. U9:25 --> Signal does not appear normal. U9:35 --> Signal does not appear normal. U9:36 --> Signal does not appear normal. U9:38 --> Signal does not appear normal. U9:40 --> Clock does not appear normal. U20:14 --> Clock does not appear normal. Could there be an issue with the address line and/or the clock? Should I replace U22? Should I replace all the logic gates U5, U6, U7, U8, U22 and U24? Thanks

I removed the Heatsink when I removed the original GPU. I want to wait and see if I get an image before installing it on the new GPU. Since I don't leave the unit on for very long when I test, I don't think it will damage the GPU. I sent an Email to Tech Support about my issue. It's really annoying since it worked for a few minutes when I first plugged it in... I will do some further testing tomorrow. Thank you.

Received my logic probe and oscilloscope. Since I replaced the BIOS with the one from Console5 which has more pins, I assume the U2 pin22 is now U2 pin24, would I be correct? I set the logic probe to pulse and CMOS. When I use the logic probe on that pin I get a low signal and when I turn on the unit or press reset, the Hi and Low lights turns on with a pulsing noise for a few seconds and then it goes back to low but sometimes it remains stuck in HI/LOW. I have attached a small video. As for the oscilloscope, I seem to have an issue with it. It worked for a few minutes when I connected it for the time, but now, I can't get a signal from either channels. Either I clicked on something that is causing this or it is defective. I just don't see any lines... VID_20191117_152002.mp4

I will take a closer look at those chips. I do not own a logic probe. Is there a model that you would recommend for a hobbyist? I saw a few cheap ones on Ebay, I don't know if they are any good. Thank you.

Here is my latest update. I have replaced the CPU and GPU with what should be compatible units (I could be wrong on this one) and I am getting the same result. I have replaced the CPU with a Toshiba TMPZ84C00AP-6 which appears to be the 6Mhz version of the Coleco CPU. I have replaced the GPU with a TMS9929ANL which appeared to have compatible specs to the the original. I am still waiting for my new Oscilloscope. Once I have it, I redo all the checks and test all the traces to try and figure out what is not working. Could it be another component that is causing the issue?

Ok, so I replaced the ROM and RAM with the ones from Console5, not luck, exact same symptoms. I am waiting for my replacement CPU and GPU. Hopefully, it will be one or the other... I'll update the thread once I have replaced them. Thanks everyone.

I get the same "Booooouuuu" sound with or without a cartridge. The weird thing is I get different wave forms with and without a cartridge but the same "Booooouuu" noise... I have put the results of U20 without a cartridge, see pictures. If the ROM is the problem, how could I test it?

I get the same results with or without a cartridge. Only a black screen with a constant "Booooouuuuu" sound. I don't see any reference on how to test U5 in the documentation that I have on hand. So I checked the voltage on U5 but I get different results every time I check. I checked with the oscilloscope and I get wave patterns on some pins, see pictures. I get the same results with or without a cartridge inserted. I am not sure how to properly test U5?

I hope that I am using the trigger function correctly. I managed to get a wave form on U9:36 using the TVH function but I get a flat line on TVV. I am not sure if it's normal. I am unable to reproduce constantly the wave form using TVH. Sometimes, it's just a flat line. It could be an issue with my old oscilloscope since I often have to fiddle with the v/Div in order to see the wave form. I have ordered a new one online, but I probably won't get it for a couple of weeks. As for the sound, I only hear a constant "Boooooooooo" sound. No music and no sound effects. Thanks

I do get a signal on 35 and 36 with the Frogger cartridge but 38 is still flat. The heat sink appears to be properly glued to U9.

Can you upload all the pages from the manual? I would love to see the entire manual. Thanks.

Thanks, I have the original manual with the oscilloscope. Here are some more tests. Nothing happens to U9:14 when I press reset.

I think my oscilloscope might be problematic. I can't seem to get a good reading. I have attached a few pictures. I was thinking of getting the Hantek PC Based USB Digital Storage Oscilloscope 6082BE 80Mhz 2CH,EXT 250MS/s. I don't want to pay too much since this is a hobby. Picture 1: pin 20 1v/[email protected] Picture 2: pin 21 1v/[email protected] Picture 3: pin 25 1v/[email protected] Picture 4: pin 27 1v/[email protected]

I ordered a TMPZ84C00AP-6 from China for 2.29$. Hopefully it will be compatible. If not, not a big lost. I am not sure if the fact that this one is rated to run at 6Mhz will cause any issues when run at 3.58Mhz. Thank you for all the help. I will update my post once I receive and replace the CPU.

Ok, so I did some testing with my old oscilloscope. I can't test everything because the oscilloscope that I have, B&K Precision 1470, does not have the ns or sub 1uS/Div range. I started testing U1:6 I am able to see the main clock on U6 by using a 2v/Div and 1uS/Div. The wave is similar but smaller on my screen. I think that the main clock is Ok. I am unable to test U1:16 since I don't have the 0.2uS/Div on my oscilloscope. When I test U1:17, I get a flat line at ±3.5v U1:18 gets a flat line at ±4.5v U1:19 gets ±1v when the switch is off which is weird. Unable to test since it requires a 0.1uS/Div U1:20 gets a flat line at ±3.65v U1:22 gets a flat line at ±3.65v U1:24 gets a flat line at ±4.5v I stopped testing since, either the oscilloscope is malfunctioning, or the CPU is dead. Does anyone know if I can get a replacement CPU other than from another Colecovision? Is there a compatible CPU that I could use?

Thank you for those documents. They will help me a lot. I do have a old oscilloscope. I will follow them and hopefully I will find the issue. I will work on it tomorrow and I will let you know if I find the issue.

Hello, I have a Colecovision that was given to me that only display a black screen with or without a cartridge inserted. I have a limited knowledge of electronics but I did some testing and here is what I have so far: - I checked the PSU and I get the proper 5v, -5v and 12v. I also tried the PSU on another Coleco and it works. I even tried another working PSU just in case. - I connected the Atari Module and I get the image. I can probably rule out the RF module. - I checked the CPU at U1 and I get a clock signal on pin6 and I get 5v on pin 11. Not sure what else I can check here. - I checked the Bios U2, U3 to U9 and all chips get 5v. - I checked the VRAM U10 to U17 and they all get the 5v, 12v and -5v. - The cartridge slot also gets 5v. Not sure what else I can check or try. Any help would be appreciated. Thank you.