TRS-80 CoCo 2 - Try to Fix - Homebrew Composite Mod

[@sylvanyoung]

Had the same sound problem with my Radio Shack TRS80 MC10 ( my first pc , decades ago 😁 . Got a C64 after ) . Thanks for peek and poke down memory lane .

[@RetroTechRepair]

So glad to bring back happy memories! The MC10 was short lived I'm afraid but like so many entry level computers it got us started on a great journey. Thanks so much for your comments

[@Mymatevince]

Really enjoyable video Roger, well done 👍

[@RetroTechRepair]

Thanks Vince. Hope you and family are all well. I'm surprised you have time to watch anything given all the great content you are putting out. Still loving the rolls series. I feel for you keeping it going over winter. As always thanks so much for your feedback.

[@Mymatevince]

@@RetroTechRepair All good thanks Roger, had a little mishap with my finger so I have to keep away from the Rolls for a few weeks. I not complaining about that though given the recent cold snap 😂

[@RetroTechRepair]

Hi vince, yes I saw your finger on the flash drive video, it must have hurt like mad (cut a bit of mine of one making dinner one time and that was bad enough) hope it was at least on the way out of the restaurant so you still got to eat. Working in cars outside this time of year is a labour of love. I did up an old porshe 944 when I lived in the states and even in a heated double garage it was bad enough in winter. My driveway in Bolton had a reliant scimitar on it for a while too that was driven on but pushed off and I had a TR7 with a similar fate. Now I only have a flat so the bike is in the hall at least. I'm still loving the content. You are doing an amazing job on that rolls and a break till spring will probably do you good. Take care. Roger

[@Mymatevince]

@@RetroTechRepair Thanks Roger, unfortunately it was on the way into the restaurant. I felt like a right idiot, first time in there and within 10 seconds all mayhem broke loose. The owner was really good to me though. Made me laugh with the drove on there, pushed off comment. If it wasn't for the fear of letting viewers down, the Rolls would be suffering the same fate😂

[@MrDaveT]

Thanks for the video. I remember playing a lot of those games on the Spectrum back in the day... Good times!

[@RetroTechRepair]

Thanks Dave glad to bring back some happy memories for you. So glad you enjoyed the video. Thanks for your feedback.

[@tomswoodwork]

Thanks for making me ancient lol. I had this exact same computer back in 1983, got it for Christmas. 16K, tape recorder, and a color tv. Spent a LOT of time on this until 1991 when I got a 386dx/33 PC. Thanks for the flashback to a simpler time, and some really cheap graphics and sound lol

[@RetroTechRepair]

Hi Tomswoodwork. LOL sorry about making you feel old (and for a delay in responding) I really enjoy this machine and its welsh "intentionally just different enough not to be a clone" the Dragon 32. I still have the CoCo, I think its probably going to be in another video soon and then maybe I'll have to move it along for my next project.

[@pickholder6189]

Do really enjoy your videos as you leave in warts and all! So many youtubers do not leave in mistakes and problems in their videos. Enjoyed this one. I do like the video game repairs as well.

[@RetroTechRepair]

Thanks Pick Holder. I do think the mistakes are a big part. I am very much an amateur at this and learn as I go so I hope my audience can learn-along. Glad that you enjoyed the video and thanks so much for your comments

[@skyway73]

Great work, a very satisfying result too. Happy New Year to you, I hope you can find time to upload in 2023, always enjoy your videos.

[@RetroTechRepair]

Thanks so much Skyway73. I will try to upload more. Promise, although I've perhaps not made a super start! I used to be able to repair small things in a day but the bigger stuff leaves me pondering for hours which isn't great viewing! Plus work and whatnot but I do expect to do better than last year. Thanks so much for your support. A real pleasure

[@ninaevans4501]

Thanks for your lovely response to our comment. Nina and myself (Wayne) carry out repairs on vintage electronics including late 70's, early to mid 80's home computers. This includes:- Sinclair ZX80 Sinclair ZX81 Sinclair ZX Spectrum 16k/48k/128k and variants Sinclair QL Commodore VIC20 Commodore 64 Commodore 16/Commodore Plus4 Commodore Amiga range BBC A/B ACORN Electron TOSHIBA MSX range That's just for starters! 😄😄😄 If you need any help, drop us a line. P.S. Not much money in repair these days, but it's still good to help each other out. Warmest Regards & Best Wishes. Wayne Brill & Nina Evans. ❤️❤️❤️😊😊😊😊👍👍👍👍👍

[@briancoulomb]

Excellent as always. That was quite the mod but the victory must have been sweet.

[@RetroTechRepair]

Thanks briancoulomb. I was very excited to get it working! Glad you enjoyed the video and thanks for the feedback.

[@8bitsinthebasement]

Great to see that you got this Coco up and running (and an NTSC version too, I'm jealous). AC's composite mod was a tonne of work but it gave great results. Ah, to be able to play Coco games in their intended colours. Another good repair video from the Retro Tech Repair stable (kittens have their place, but don't give up the retro stuff). A very happy new year to you and yours Roger, take care ;)

[@RetroTechRepair]

Thanks 8BITB (OOOhh I have just noticed how clever your channel name is) anyhow. Happy new year to you too. According to the CoCo manual the TRS80 has an "artifacting circuit" so it was very much the intention of the designers to use the feature and I feel if it had been possible on a PAL Dragon 32 then the Dragon might have done a little better in the 8-bit wars... poor dragon. Anyhow, thanks so much for your comments. Hope that you are enjoying your well earned break.

[@ghost-retro3733]

Great video as always. If you’re like me, you get a great sense of achievement when you build (or in this case rebuild something) from a set of schematics or step by step instructions. I recently built a Spectrum 128 Harlequin from scratch (the hardest part was sourcing all of the parts). When I first turned it on and got the good old spectrum 128 menu screen, I was shouting yes..F**king yes yes like a madman. I sometime struggle with confidence in my abilities, so this gave me a massive boost. Anyway, thanks for your all your videos.

[@RetroTechRepair]

That's great ghost Excellent job with the spectrum. Congratulations. I haven't done anything like that myself. Thanks so much for your comments

[@ghost-retro3733]

@Retro Tech Repair No worries, Your channel is one of my favourites.

[@RetroTechRepair]

@@ghost-retro3733 that's great to hear

[@matthewbeeson5612]

Happy New Year Roger! That was one long journey indeed, yes I stuck it out for the full video! Great result and for me would be worth it for a few games of Chuckie Egg alone!

[@RetroTechRepair]

Thanks Matt, I must admit I played chuckie egg quite a bit! Glad you enjoyed the video. Happy new year and as ever a massive thank you for your support

[@matthewbeeson5612]

@@RetroTechRepair Hope your e-bike project is going well.

[@RetroTechRepair]

Errrrhhh .... it's going slowly? I'd expect an update before too long, but I'd also expect to be underwhelmed!

[@maltronik]

I like it this way.. Really… people always say to me mistakes are good for learning.. and since that you made them and I learn from them so and appriciatetion is in order. So thank you so much for making this video..❤

[@RetroTechRepair]

Thank You Zulkarnain Adnan. I did learn a lot repairing this COCO. Thanks so much for your comments. have a great new year

[@maltronik]

@@RetroTechRepair happy new year to you too..

[@richardhowarth1659]

Happy New Year Roger, another very enjoyable video. Many thanks.

[@RetroTechRepair]

Cheers Richard... and to you too. Glad that you enjoyed the video

[@K.P.Alexander]

Nice work on that one! Also, amazing how good of a tune you could get out of these things (Dunjunz intro).

[@RetroTechRepair]

Thanks KP... isn't it (Dunjunz). Sadly it takes a lot of processing time to do it so its restricted to intro's as I'm game sounds takes CPU time. Airball has a nice intro tune too. Glad that you enjoyed the video. Thanks much for your comments.

[@telemedic5142]

I have the same machine with the same mods. The display after the mod is pretty good. It’s nice to know there is another ntsc one in the uk!

[@RetroTechRepair]

Glad you enjoyed the vid. I actually bought the NTSC version by accident from a (deliberately?) vague ebay add in the UK, but on balance I am very pleased it went that way. Did you replace the transformer or do you just run off a step-down?

[@telemedic5142]

Actually, I was looking for an ntsc machine and put a post on the coco Facebook page. And a kind gentleman from the USA offered to send me the board and the keyboard, as he was going to fit a raspberry pi in its case. So all I have is that, but I’m very pleased with it.

[@WhoopsWonders]

come over from my mate vince channel. looking forward to checking out your videos 👍

[@RetroTechRepair]

Welcome aboard! Vince is legend. Happy to have you here. Thanks for the comment. Appreciate it!

[@WhoopsWonders]

@@RetroTechRepair No worries. yeah vince is great. been watching his vids for a long time. im glad i found your channel retro fixes is right up my street. liked and subbed your channel

[@RetroTechRepair]

@@WhoopsWonders that's great. Thanks

[@ninaevans4501]

Oh, and just watched your last vid on TRS80 colour mod. Migraine time 😄😄😄😄😄

[@RetroTechRepair]

Yeah.... I wanted to find a way to show the scale of the mod and give AC credit without hurting everyones eyes or being too boring. Not sure if I managed it. LOL

[@natethefighter]

Don't know if anyone has mentioned it yet (didn't see it after skimming through the comments), but the yellow stripe, aka "yellow bar problem" is common on CoCo2s. There's a yellow color burst circuit on the main board that corrects the colors in hi-res mode so that they're red and blue instead of purple and green. On mine, I replaced the germanium diode and the 555 timer and all was well.

[@RetroTechRepair]

Oh wow... no nobody mentioned that! Fantastic information... I was about ready to part with the coco 2 but now i have another project! Thanks so very much

[@CoCoNutBob]

Is there info to accomplish this tuning on a CoCo 1 (rev F)? No 555 timer.

[@natethefighter]

@La CoCo Strangiato I'm not aware that CoCo1s have this problem because they don't need a yellow color burst. The computer generates the orange and blue colors natively. The CoCo2 needs this circuit to generate those correct colors due to minute changes in circuitry which cause the artifact colors to be green and pink instead.

[@CoCoNutBob]

@@natethefighter I have a CoCo 1 with a composite mod that causes the RF artifacts to shift to green and purple. It used to affect composite too, but I stripped out unneeded components from the composite board and composite now outputs red/blue.

[@natethefighter]

@La CoCo Strangiato wild how just a little bit of otherwise-pertectly-fine tinkering can screw with those artifact colors!

[@Wenlocktvdx]

A/V mod is definitely better than rf. Interesting way to do it too. Pretty sure that coil wouldn’t have enough range to reach the correct frequency anyway.

[@RetroTechRepair]

Thanks Wenlock that makes me feel better

[@Wenlocktvdx]

Glad it helped. I used to have a lot of trouble at times as VHF modulators were used in Australia and the CoCo would produce a lot of interference so I had my R.F. cable wound round a ferrite rod

[@David_Ladd]

The yellow color bar on the left could be a aging 555 timer chip. Might have to replace that chip. That is one of the fixes for that.

[@RetroTechRepair]

Thanks David. I've ordered some and expect to revisit in a future video. Really appreciate it!

[@David_Ladd]

@@RetroTechRepair , Happy to pass it on! :D Keep up the good work. :)

[@jasejj]

Was this a re-upload of the earlier one because of the smearing / jerky video? Nice video, and interesting to see the Apple style artefact colour - makes the machine a lot more competitive. In PAL mode the graphics are, let's face it, a bit lame, even compared to the Speccy or Oric.

[@RetroTechRepair]

Yes... the smearing is new and I have no idea why. Its exported via apple compressor using identical settings to those I have used for years. It was not supposed to be released but I guess I forgot to cancel the schedule. The new one comes straight from final cut Pro and is hopefully better. Thanks again for your kind words.

[@CoCoNutBob]

"... but as we will see, there will be soon." 😂

[@RetroTechRepair]

Glad you liked it! thanks of the comment!

[@arenotdiy]

My kitten is malfunctioning, a repair video would be great ;)

[@RetroTechRepair]

LOL... sometimes I can't repair stuff and it ends up in the bin. My cat is getting extremely worried.

[@alisondenu5317]

Those yellow lines might be from the color burst timing circuit, Joe over at Joe's Computer Museum had that issue and repaired it in a very brief but interesting video: kzbin.info/www/bejne/p3nSm3qso9N1aaM

[@RetroTechRepair]

Thanks.... a couple of other people suggested that too, I might do a video on it myself. Thanks so much for the suggestion!

[@Relaxing_Lee]

Your voice reminds me of Jeremy Irons lol

[@RetroTechRepair]

I'll take that as a compliment! Thanks!

[@Relaxing_Lee]

@@RetroTechRepair it's definitely a compliment 🙂

[@matthewbeeson5612]

I was thinking more Greg Davies (for those comedy moments!)

[@Relaxing_Lee]

@@matthewbeeson5612 lol he does dude 👍

[@ninaevans4501]

Oh and finaly, may we strongly recommend watching the videos of that fantastic guy Chris at Gadgetuk164. Certain parts for Commodore64 and Sinclair Spectrum, can be obtained from Mr Phil Ruston (Retroleum Computer Spares). 👍👍👍👍👍

[@RetroTechRepair]

Thanks Wayne... I have been watching Chris a Long time actually, way before I started this channel, love his content. Thanks for the parts tip! I'll check the out. Appreciate the support