Really fixing the CRT spot on the Commodore PET 2001
Vložit
- čas přidán 4. 06. 2024
- In part 1, I tried to fix the spot on my PET's CRT but the spot fix didn't work. So in this video, let's get to the bottom of the spot once and for all. For a better and more in depth technical explanations of the cause of the spot and the fix, please watch Frank's (IZ8DWF) video on the subject:
• Fixing the 9" PET's mo...
Part 1: • Permanent Killer Poke ...
Part 2: This part!
0:00 Intro
1:31 Trying a better 8.2V zener diode
3:42 Swapping a transistor
4:50 Warning: Don't install a focus pot
9:11 Trying a different CRT in the PET
10:67 Running the CRT heater from an external PSU
15:01 Applying the spot fix to a different PET 2001 as a test
19:12 PET CRT difference revisions?
25:11 Examining the schematics to find other problems
29:48 Applying the final fix to my PET 2001
33:22 The PET Spot fix summary including diagrams
37:28 Outro
Parts used:
Vishay 8.2v Zener Diode
BZX55C8V2-TAP
Vishay 33v Zener Diode 1.3W
1N4752A-TAP
Vishay 2.2k ohm resistor, 2 watts
PR02000202201JA100
Parts to change for the spot fix:
C22 -) If it's 3.3uf, replace with 47uf/50v
R5 -) If it's less than 2.2k ohm like 1.5k, replace with 2.2k ohm 2 watt resistor
CR7 -) If R5 above was less than 2.2k ohm, replace CR7 with a new 33V 1.3 watt Zener diode.
R2 -) On all revisions, replace resistor R2 with a 8.2v Zener and 470 ohm resistor in series
--- Video Links
Frank's (IZ8DWF) Fix explanation and results:
• Fixing the 9" PET's mo...
/ @iz8dwf
Chuck Hutchins' fix results:
• Suppressing "the spot"
/ @hutchca
Zimmers.net Schematics for the 2001:
www.zimmers.net/anonftp/pub/cb...
--- Tools
Deoxit D5:
amzn.to/2VvOKy1
store.caig.com/s.nl/it.A/id.16...
Jonard Tools EX-2 Chip Extractor:
amzn.to/2VazxDS
www.jonard.com/Products/EX-2-...
Wiha Chip Lifter:
amzn.to/3a9ftWw
www.wihatools.com/precision-c...
O-Ring Pick Set: (I use these to lift chips off boards)
amzn.to/3a9x54J
Elenco Electronics LP-560 Logic Probe:
amzn.to/2VrT5lW
Hakko FR301 Desoldering Iron:
amzn.to/2ye6xC0
Rigol DS1054Z Four Channel Oscilloscope:
www.rigolna.com/products/digi...
Head Worn Magnifying Goggles / Dual Lens Flip-In Head Magnifier:
amzn.to/3adRbuy
TL866II Plus Chip Tester and EPROM programmer: (The MiniPro)
amzn.to/2wG4tlP
www.aliexpress.com/item/33000...
TS100 Soldering Iron:
amzn.to/2K36dJ5
www.ebay.com/itm/TS100-65W-MI...
EEVBlog 121GW Multimeter:
www.eevblog.com/product/121gw/
DSLogic Basic Logic Analyzer:
amzn.to/2RDSDQw
www.ebay.com/itm/USB-Logic-DS...
Magnetic Screw Holder:
amzn.to/3b8LOhG
www.harborfreight.com/4-inch-...
Universal ZIP sockets: (clones, used on my ZIF-64 test machine)
www.ebay.com/itm/14-16-18-20-...
RetroTink 2X Upconverter: (to hook up something like a C64 to HDMI)
www.retrotink.com/
Plato (Clone) Side Cutters: (order five)
www.ebay.com/itm/1-2-5-10PCS-...
Heat Sinks:
www.aliexpress.com/item/32537...
Little squeezy bottles: (available elsewhere too)
amzn.to/3b8LOOI
--- Links
My GitHub repository:
github.com/misterblack1?tab=r...
Commodore Computer Club / Vancouver, WA - Portland, OR - PDX Commodore Users Group
www.commodorecomputerclub.com/
--- Instructional videos
My video on damage-free chip removal:
• How to remove chips wi...
--- Music
Intro music and other tracks by:
Nathan Divino
@itsnathandivino
Outro Music:
Abyss by | e s c p | escp-music.bandcamp.com
Music promoted by www.free-stock-music.com
Attribution 4.0 International (CC BY 4.0)
creativecommons.org/licenses/... - Věda a technologie
Adrian has this 'never say die' attitude, that you gotta admire
I love it. It keeps me going on my projects that I have come to dead ends on of my own.
Agreed. Something I used to have, but it has waned somewhat in the past few years ... sigh!
If he had been a doctor he'd go the way of Dr Frankenstein for sure.
@Michael O Callaghan I tend to buy things from either local flea markets and thriftstores, or even ebay that are broken, just to try to fix them. lol
@Michael O Callaghan that hows ya learn. or at least how i did. Right now im working on a NES console that someone lifted 80% of the traces on cuz they didnt know what they were doing. I told them i could probably fix, but now they know not how to do it lol
My first 12” black and white tv had a white dot minutes after turning off...
My parents knew this so when I heard steps on the stairs I was already to late 😂
Hahaha foiled by a bad design!!
Too*
@@Wewewea No, they were correct by saying "to" .. By being a grammar nazi, you made yourself look like a muppet!
@@EzeePosseTV You’re obviously wrong. ‘To’ is a preposition and ‘too’ is an adverb.
@@Wewewea Turning brightness to 0/zero is the correct way to say it. But saying "turning brightness too 0/zero" makes no sense. Google, Bing and Duck Duck Go agree with me. Just like saying "I'm going to work/going to correct you/going to turn my volume to 0/zero" am I wrong?
Adrian's gonna have that thing running at 800x600, full color, with a GUI driven Commodore BASIC interface by the time this is all over! :)
Then it will gain sentience and kill us all! No, Adrian no!
Replace the mainboard with a Raspberry Pi and the CRT with a 4K LCD panel.
@@Okurka. That would be blasphemous to such a beautiful and classic computer to put that crap in it.
yeah but i bet the spot will stil show up :_:
Adrian is gay? Awesome! No have many gays in old eletronic
Excuse my language, but holy fucking shit. My dad has a older model PET 2001 where the bright spot has bothered him for the last 15-20 years. When mentioning it, its all he ever talks about and how he could never get it fixed. I'm going to "borrow" his PET '01 and apply these fixes as a Christmas present. Thank you so, so much Adrian! Greetings from Norway!
"Out, damned spot!"
--William Shakespeare...
at the drycleaner?
Vamoose ya little varmint !
I was going to go there, but you beat me to it.
"Begone, thou foul, malingering spot!"
@@knghtbrd Ditto. Like minds think alike! That line is also from Macbeth, FYI.
You are the retro-world's best troubleshooter.
The thing is, while he's trouble shooting, he's not an engineer, he's learning along the way. We are picking up, what he's putting down. He tries, isn't afraid, and this is working out well for him and the rest of us.
It was now a matter of principle, to eliminate that spot!!
Man vs Dot! - new exciting series!
This man is a professional, despite not having degrees in electronics.
Adrian your perseverance is so high that you really inspire other people to be like you. Good Job!
I've never been so on the edge of my seat while awaiting the arrival of a spot!
Except maybe that time involving a pregnancy test?
Thrilling as a sports match! I was actually shouting out loud "Ohh nooo!" when the capacitor didn't fully fix it. Great to see you getting to the bottom of this. Well done!
Funny enough, the entire time of it not being fixed (at this stage I mean) I was screaming in my head - get to a cap dude! I was for sure that once he did, it was a done deal. hahaha
The diode wasn't zen enough, I need a zener diode ...
Ok, I'll get out ...
One that's not so prone to breakdowns?
Puns are art by my book and have to be appreciated. That one was quite good!
😂😂😂 I assume you’ll let yourself out...
no no, don't leave. I'll be here all night. Please, stick around. I can't resist a good pun.
@@Kylefassbinderful
What happened to the overheated magnet?
He gave up the Gauss.
I can't express how much I enjoyed this video. I really appreciate your perseverance. It was an amazing journey. Thank you for taking us through it step by step.
I have never in my life felt so much suspense over a dot. 😂🤣😂 Thanks for the great video!
Adrian, at times you are really 'hardcore'. That spot must have REALLY been buggin' you. Good work!
I don’t know how but Adrian suddenly got me interested in a pesky spot in a ‘70s machine that I never really cared for. Love you Adrian for making such engaging content and providing so many hours of great entertainment! Keep up the great content!
For a better and more in depth technical explanations of the cause of the spot and the fix, please watch Frank's (IZ8DWF) video on the subject:
czcams.com/video/WULJxrQkQeg/video.html
Update: Chuck has applied the fix to his monitor as well, see his results here: czcams.com/video/iMSQTCdC-jg/video.html
🎃
Adrian, I would strongly suggest replacing ALL the electrolytics. As you noted, the ESR of those caps are pretty bad. They are after all 50 years old. Heat and age are not doing them any favors.
Just did the mod of changing R2 2k2 to 470R in series with 8.2 zener on a 3032 PET. The rest of the components are already at the correct values. The annoying spot has gone. Thank you Adrian and Frank!
Hi Adrian, thanks a lot for all this amazing content you upload. I’m 20 years old, I’ve never seen, used or even heard of any of the devices you show in your videos but somehow I can’t get my eyes away from the screen from the moment they begin to the moment they end! It never happened to me before, I guess that’s what happens when you find a genuinely interesting and talented youtuber.
What a rollercoaster. Every time I was holding my breath, waiting to see if the dot appears.
This is very interesting - I have a 2001-8 with chicklet keyboard and tape which I've had since 1979 (well, my dad bought it but I commandeered it!) and needs refurbing someday. I'll keep a note of this video for when its time comes (which hopefully will be 2021!)
I remember back in '85 when I last used it I would get a faint spot a few seconds after turning it off (only really visible in a darkened room) that lasted for a minute or two. Since its been unused for ~35 years its going to need a complete refurb and I will put in the mod and check the 33v Zener!
Great channel Adrian, I found you through one of your earlier PET videos. Theres not a huge amount on CZcams with these PETs, most of the attention these days is on the later more glamourous machines, but I learnt to code on my (*cough* Dads) PET and the skills it taught me have been good to me in my working life.
On another note, are you trying to collect ALL the SIM RAM in the world? :D Say Hi to Rammy for me!
Great mini-series, I am now emotionally invested into the state of Chuck's PET, hope the fix works for him as well!
Glad you persisted with it.
After following the first part I was disappointed when I saw the Pet reassembled initially but not fully fixed.
This really gives a new meaning to a Spotfix on your computer.
Perseverance pays off in the end. Great Job!
The drama that comes from the waiting for the dot to appear is fantastic. Thanks for another great video.
what an amazing example of archaeology!! tracing previous repairs from another era, beautiful stuff
I love when you find a solution for a problem! Congrats!
Well done Adrian, nice to know what the actual problem was, cheers!
Realy fantastic your perseverance to fixing that problem.
Congratulations!!!
Fair do's Richard Dreyfuss. Your tenacity earns you a subscriber.
Glad you finally got this fixed and what a way to end 2020. Never before in CZcams history has staring at a black screen been so exciting.
This video was extreme satisfying. I’m glad you never gave up on fixing it
I love watching the methodical way you troubleshoot these problems, Adrian! It's great to share a part of the satisfaction once these tricky bugs are sqaushed. Great work as always!
The 'R2 -) On all revisions, replace resistor R2 with a 8.2v Zener and 470 ohm resistor in series' fixed my 2001...thank you
This was a thriller with a lot of plot twists. Very interesting, thank you!
This was a GREAT video. It really shows how such a seemingly small issue can eat up so much time.
My parents used to admonish me for watching too much Tv as a child (40+ years ago)......."You would watch the dot" they would say....now i know what they meant !!
You have the dedication of a scientist. Very well done!
No joke, one of the most rivetting and thrilling set of videos I've ever watched on CZcams. A retro electronics drama like no other!
That is the best feeling ever, working on something and trying diffrent things multiple times, and FINALLY fixing it. 😃😃
Great work Adrian! I can imagine how much work it was to fix this. Sometimes things are looking so simple in the videos, like it took 10 Minutes to fix it, but sometimes you have to try it again and again and it actually takes months. I know it too good :) Thumbs up!
Great content. You do not give up fixing a problem until it is solved. I like that. Keep it up!!
I own both a chiclet 2001 (1st revision analog board) and a 2001-N (2nd revision analog board).
After applying the spot fixes according to your video, the 2001-N has been spot-free for a year now. I can't draw a conclusion on the chiclet 2001 yet as I only got it properly running a few days ago, but so far the fix seems to do its job very well.
More ups and downs than a thriller movie!! Nice work.
Adrian, I don't own a Pet but Your commitment to solve the problem is simply remarkable
I think the spot was the PET's soul and you killed it :(
:D
Job's Garage well that got depressing fast
Hi @Adrian's Digital Basement, another great video, I love problem solving videos, it is nice to know I am not the only one that has to spend ages fixing issues like this, looking forward to the next one. 👍
Fascinating. I wasn't sure that you were going to find the solution to this problem. But then again, who am I kidding -- great job -- and process duly noted. I have two PETs yet to be tended to and I will be sure to remember this great solution. 👍
That was great, one of the best troubleshooting vids I've seen. I'm old enough to have, in a previous life, to have been CRT TV repairman. This brought back memories.
It's funny that as this came up in my feed I am working on editing my video about fixing an IBM 5154. So, I have something very relevant to watch while I wait for rendering to happen. Thanks!
Congratulations on this particular video. It is clearly perceived the large amount of work behind. Researching, exchanging impressions with colleagues or mounting / dismounting the monitors with which you have done the tests.
Really excellent video Adrian, fascinating stuff and pretty awesome to see a working fix in the end!
23:39 I had a Mitsubishi TV from the 1973 with that instant-on feature. It did run the heater at reduced voltage so didn't cause any significant tube life issue. The TV got scrapped a few years ago, just because no-one wanted it, but it still worked!
33:12 I've never thought to keep a dead parts bin. Mine would be very full indeed by now, mostly of smelly electrolytic capacitors.
Your determination is admirable as all hell. Bravo good sir.
Great video Adrian, well done for finally fixing the monitor issue. Keep up the great work!
Never had so much fun watching a spot .We need this to a be yearly event , spot watching 2021.I'm kidding of course , great vid . I hope you and your viewers have a great year in 2021
West of house
You see an interesting house with a locked door.
There is a mailbox here full of packages.
To the north you see a basement entrance.
> Enter basement.
A SPOT HAS APPEARED!!!
>
Yay, Adrian! I am glad you found this issue with that light spot. You are like the Sherlock Holmes of circuit troubleshooting!
Nice congrats that you finally fixed it! Nice job documenting everything hopefully this helps other pet owners with this annoying problem
Really enjoyed this. Glad you stuck with it and persevered.
I love this troubleshooting adventure and great investigation and explanation. Personally I'm lazy and would have just lived with it as I've never seen an original PET with any burn-in from 'the spot', and I actually find it kind of charming, like some ancient TVs that did this when I was a kid. I have a next-gen PET, a 2001 (3032) "Professional Computer" and it does not suffer from the spot though.
That model with the chicklet keyboard and built-in cassette drive was where I first saw the "Hunt The Wumpus" game. I recorded the tunnel connections onto paper and wrote my own version of the game using just that information along with the knowledge that there were exactly two pits and exactly two caves with bats. 😄
Anyway, grats on fixing the problem.
15:30 The left PET 2001 is a personal computer, the other PET 2001 is a professional computer.
Nice catch!
Nice to see you figured it out in the end! First thing I noticed that was different was the flyback transformer design, as you mentioned, but I just guessed that perhaps Commodore had a different manufacturer for the later ones.
The flyback transformer was the first thing I noticed being different.
Wish I could give you 10,000 likes! Congratulations. What a quest :D Nice job to all involved but Adrian your persistence is what solved this. I find this type of content so satisfying it's like defeating a boss at the end of a 200hr game.
Wonderful diagnosis and great information.
An awesome effort Adrian... well done.
Im always in awe of the efforts and time you devote for such a noble goal of maintening those pieces of history, kudos sir keep them coming, always very enjoyable. ( and kudos to the wifey too for enabling you for our enjoyement xD )
One of your best videos.
Well done... "Out damned Spot" I love this type challenging troubleshooting to resolve a complex problem
The "dot" is residual charge left behind somewhere and released (discharged) into the monitor, the trick would be to find the part of the circuit that is responsible for fast discharge after the monitor has been turned off. The voltage affects the X/Y positioning of the beam, so... technically that could be a thing too.
Nice work Adrian, you've been very committed to fixing this one little problem and I'm glad you got it sorted. (How did this video get dislikes?! Seriously, this is dedication!)
Such patience. Time to dig out my PET and get it fixed too.
Hahaha, I love it... using a desoldering station till solder. The irony and upright frankness about doing so. That settles it, Im sending a Christmas present.
Sweet victory! Congratulations sir.
Adrian, you're simply awesome
4.4K likes, 43 dislikes, yep I think that sums up how enjoyable this series is. I'm very much an electronics newbie though I used to build computers to pay my way through Uni in the 90s. This would be beyond me but I've learnt a lot. Thank you.
Excellent work! My 2001 has a very nasty spot so I should investigate this.
You just made me watch spots for forty minutes, congratulations
unrelated, but one of my family's last TVs lasted about 12 years, until we replaced it with a flat panel we got from a family member, we replaced it because it was taking upwards of 2 minutes to warm up, when usually it only takes about 10-30 seconds. it was a zenith i believe. I think that's very good life for being turned on for at least 14 hours a day for 12 years, and knowing my dad, we probably got it used so add that on top.
Excellent TUTORIAL!
15:27 - the differences are down to yours catering to the home/personal market the loan one catering to the professional market, the green screen was considered to reduce eye fatigue, the keyboard also was a better design (IIRC they where hall effect switches rather than the traditional mechanical ones)
So youtube commentators noticed the spot on your monitor, which is perfectly normal for the crt's of the era, but they don't know about it because back then their parents were in elementary school. They told you that this is indicative of a fault and your CRT will explode. This is not true and they told you that either to have a laugh at your expense or to boost their paper-thin ego and pretend they know something about something. And now we have 2 very entertaining videos, and you spent month trying to fix a non-issue and finally fixed it.
Great video as always!
Adrian I received the parts today and got them installed. I did all the mods as well as replacing all the older capacitors. Guess what no more dot!!
What an ordeal to sort it out. Great work. Next how about a Mod to convert the display output from the CRT to a more modern LCD display.
Glad you got yours figured out, crt are a nightmare 70% science and 30% art.
I said "One hour latairrr" about 15 seconds before you added that in.
Don’t be so sure about the spark gaps... unless they’re sealed, dirt and corrosion could get in the space between the gap, causing leakage.
Truly excellent work - thx
Great video!! Really tricky failure and very entertaining root cause analysis. 👍🏻. Greetings from CPUGALAXY 🇦🇹
It took me until 33:50 when you mentioned 47 microfarad for C22 to actually realize that it was 47. Earlier in the video when you applied the actual fix, I was thinking 4.7 the whole time. I made a comment trying to correct what I saw and heard but deleted it as you are correct in your video throughout. I am glad for you and enjoy!
Hello Adrian from Nottingham UK.
Just want to show my total and absolute appreciation for the effort you put into your videos my friend.
My GOTO to escape from the nonsensical human malware that we're all suffering through ATM.
Please Please keep up the astronomical effort you are putting into these fantastic recordings.
It is truly the very best channel available on CZcams right now.
Both you and Mark fixes stuff are keeping me sane lmao 👾🕹️😂.
Love what you are doing Mr. Black..
Hey!!!
You should be a character on a Captain Scarlet hehe he 😂
What a roller coaster ride that was 😅 Well done sticking with it all this time.
Nice job. Keep up the great work.
I wonder if that zener is really bad. It may not be. As you said, all semiconductors tend to leak when hot. Just because that diode was leaky when hot, does not mean it has failed. Just changing the dropping resistor may have fixed the issue.
Pro tip: When trying fixes, try to change only one variable at a time. If you change two parts, and the problem is fixed, which part was actually bad? Potentially none. The resistor was obviously fine, the zener may have had issues, but now we'll never know. I would have changed the resistor first (too small a dropping resistor is a n00b mistake, commodore), and tested.
But swapping the zener out certainly did no harm, so there is that.