Hi there, I have replaced R920 to its nominal value and sure enough I'm getting 78V @80V test point. Close enough. Unfortunately no HV whatsoever. There's >100V on HOT's collector so it looks good. I didn't have much time to troubleshoot it further. Is there any marking on the flyback? You know, just in case...
Cheers, Mateusz W dniu niedziela, 4 marca 2018 18:16:58 UTC+1 użytkownik zgbapl napisał: > > Hi Keith, > > >> Have you tested the expected voltages at the various test points on the > circuit boards? > > sort of. I'm getting ~100V instead of expected 80V at R920 which is, as > per your measurements, a little bit off. I will replace the 47k resistor > with a proper 27k one and check the voltage again. > > >> Also, you may have to test continuity between pads in case of hairline > cracks in the tracks. > > Yeah, that will be my step two if the resistor replacement fails. > > Apart from that I'd like to hook up my scope to see some waveforms, but I > don't have a separation transformer (yet) so that would be my last > resort... I'm not giving up though. > > W dniu niedziela, 4 marca 2018 14:23:43 UTC+1 użytkownik Mat Stalkman > napisał: >> >> Hi Mateusz, >> >> Sorry, been away from the emails for a few days. >> >> I have tested the following resistors out of circuit on my European >> board. Colours are as per my board. >> >> R523 - Brown-Red-Orange - 1-2-000 - Measured 11.7k >> R919 - Brown-Black-Orange - 1-0-000 - Measured 9.7k >> R920 - Red-Violet-Orange - 2-7-000 - Measured 26.9k >> >> Hope this helps, >> >> Keith. >> >> On Saturday, 3 March 2018, 14:55:15 GMT, zgbapl <zg...@o2.pl> wrote: >> >> >> Hi Guys, >> >> I managed to rebuild the board and despite my curiosity wants me to power >> this thing on immediately to see if it works, I'd like to check those last >> resistors to be sure that I won't damage the circuitry. Here it goes: >> >> R523 - 12k, my guess was 22k >> R919 - 10k, my guess was 56k >> R920 - 47k, my guess was 27k >> >> Please check them for me, and let's see if it powers up:) In the meantime >> I will clean the rest of wires, connectors etc. and start writing my story >> :) If you confirm those values I will publish my sheet where I have written >> down most of the parts (without inductors, transformers etc) and their >> values. The schematic is on its way. >> >> Cheers, >> Mateusz >> >> W dniu sobota, 24 lutego 2018 14:50:49 UTC+1 użytkownik Mat Stalkman >> napisał: >> >> Mateusz, >> >> I have metered the following resistors, out of circuit. >> >> R423 - Blue-Grey-Black-Red - 6-8-0-x10^2 - 68k - Measured 67.6k >> >> R506 - Blue-Grey-Red - 6-8-x10^2 - 6.8k - Measured 6.85k >> >> R419 - Brown-Red-Gold - 1-2-x10^-1 - 1.2R - Measured 1.3R >> >> R511 - Brown-Black-Black - 1-0-x10^0 - 10R - Measured 9.9R >> >> R514 - Brown-Black-Black - 1-0-x10^0 - 10R - Measured 9.9R >> >> R526 - Brown-Red-Gold - 1-2-x10^-1 - 1.2R - Measured 1.3R >> >> R911 - Printed 0.33R - Measured 00.3R (I don't have a lower scale for >> additional decimal places) >> >> Hope this helps , >> >> Cheers, >> >> Keith >> >> On Thursday, 22 February 2018, 19:10:23 GMT, zgbapl <zg...@o2.pl> wrote: >> >> >> Hi Guys, >> >> the main board is pretty much complete now. I'm only missing a few parts >> now. I'd like to ask you to double check those two resistors: >> >> R423 - my initial guess (I don't remember if I measured it or read the >> stripes) was 6,8K, but you guys say it's 68K >> R506 - the other way round - in my sheet it's 68K, not 6,8K >> >> Additionally I'm not 100% sure if I got those power resistors right: >> >> R419, R526 - 1,2 ohm >> R511, R514 - 10 ohm >> R911 - 0,33 ohm >> >> Hopefully I got it all right. Keep the fingers crossed. >> >> Cheers, >> Mateusz >> >> W dniu wtorek, 20 lutego 2018 21:59:16 UTC+1 użytkownik The One True >> Stickman napisał: >> >> Yes, Keith also measured this one at 160K after I posted my initial list. >> Out-of-circuit test confirms 160K, so there's a triple-check! >> >> On Tue, Feb 20, 2018 at 6:05 AM, zgbapl <zg...@o2.pl> wrote: >> >> >> Typo - 86 makes no sense for R521, I think it must either be 76 or 16 >> ohm. >> >> I think I have measured this one and it's more like 160K 1%. Maybe you >> could measure it in-circuit? I will do the same with 160K resistor soldered >> in and compare the results. That's the biggest difference between my >> measurements and your readings so far, so it would be nice to double check >> it. >> >> W dniu piątek, 2 lutego 2018 14:14:54 UTC+1 użytkownik The One True >> Stickman napisał: >> >> Typo - 86 makes no sense for R521, I think it must either be 76 or 16 >> ohm. >> >> On Tue, Jan 30, 2018 at 7:58 PM, <theonetru...@gmail.com> wrote: >> >> Added to the folder - in case colors aren't visible, here are resistor >> codes & values. All appear to be 1/8W carbon 5% except R521 & R423, which >> look like a 1% metal film: >> >> R919 10K (Brown Black Orange) >> R920 47K (Red Violet Orange) >> R521 86ohm? (Violet Blue Black Gold 1% metal film - this one is hard to >> read) >> R523 12K (Brown Red Orange) >> R423 68K (Blue Grey Black Red 1% metal film) >> R506 6K8 (Blue Grey Red) >> >> Let me know if you need anything else, I didn't have more than a few >> minutes today. >> >> I'd bet the only real difference between the US & European model is in >> the line voltage power supply side of the board and the rest is pretty >> similar. There's a photo of the entire board and one of just the signals/HV >> side. >> For future searchers: I will upload these all to flickr or imgur as well >> and post the link, as I won't keep them in dropbox forever. >> >> >> >> On Tue, Jan 30, 2018 at 1:57 AM, zgbapl <zg...@o2.pl> wrote: >> >> >> is yours also a US model or an international? >> >> It's an european one. Seems like there are some differences between our >> models. Still, I'd like to see a few close shots of your board. >> >> So if you could take a pic of the following elements, that would be >> great. To make it easier, I'm gonna tell you rough directions (my board is >> facing the flyback down, so the CRT is on my right hand side) and their >> orientation. >> >> R919, R920 - two small ones, center right (under the CRT neck) in close >> proximity of Q905 transistor (with a big heat sink) and two blue disc caps; >> vertical >> R521 - near the flyback transformer, slightly above and on the left; >> horizontal >> R523 - slightly lower than the previous one; horizontal >> R423 - left to the J501 (vertical connector, lots of wires); horizontal >> R506 - far bottom left, above H-hold pot; horizontal >> >> Those are the troublesome ones. Please take a picture of the underside of >> the board - even if they are slightly different, I should be able to figure >> out the differences by looking at the connections. >> >> Many thanks. >> Mateusz >> >> W dniu wtorek, 30 stycznia 2018 00:19:06 UTC+1 użytkownik The One True >> Stickman napisał: >> >> Mine is an M1296 110V/60Hz US model, no G suffix - is yours also a US >> model or an international? Some photos linked below, I can pull the boards >> out if needed. >> >> https://www.dropbox.com/sh/ 9s390k8gcva62e4/ >> AABptFdkwVknxSDRcH_zyi40a?dl=0 >> <https://www.google.com/url?q=https%3A%2F%2Fwww.dropbox.com%2Fsh%2F9s390k8gcva62e4%2FAABptFdkwVknxSDRcH_zyi40a%3Fdl%3D0&sa=D&sntz=1&usg=AFQjCNFUXsgjhDrU1UsJR0EwscrU8WJr9A> >> >> On Mon, Jan 29, 2018 at 8:49 AM, zgbapl <zg...@o2.pl> wrote: >> >> Oh, that would be great. If you don't mind, I'd tell you which close-ups >> I need the most. >> >> BR, >> Mateusz >> >> W dniu poniedziałek, 29 stycznia 2018 14:12:23 UTC+1 użytkownik The One >> True Stickman napisał: >> >> I think I have this monitor, but will have to dig it out of the closet to >> check. If my memory is correct I'd be happy to grab some photos in the next >> couple days >> >> On Mon, Jan 29, 2018 at 5:22 AM, zgbapl <zg...@o2.pl> wrote: >> >> Hello there, >> >> some time ago I got my first Mac ever - an LCII with a 12" RGB Monitor. >> The whole setup was stored in a moist basement and unfortunately somebody >> has spilled some washing powder all over it. It turns out that this stuff >> is even more corrosive than battery acid. The computer itself was in a >> relative good condition. I had to replace some components, repair two >> broken traces and give it a good clean and after that it happens to work >> just fine. >> >> The monitor is a different story. It was very badly corroded, especially >> resistors were covered with rust. I have desoldered all of them but a few >> of them were faulty and I couldn't measure their values. Color bars were >> either washed out or totally covered with rust. I have figured out most of >> them but I still have some pure guesses. There's no (useful) service manual >> or schematic I could use. >> >> Before anybody tells me no to bother - I know that this stuff is neither >> vintage nor rare, but I'm really having fun trying to rescue old hardware. >> Right now I'm at the point where the PCB is totally emptied of any parts >> and once I fix the traces and cover them back with solder mask, I will >> start re-populating the board. >> >> TL;DR - is there anybody out there willing to disassemble his M1296G and >> take a few photos of the main board? >> >> Thanks a lot. >> >> BR, >> Mateusz >> >> -- >> -- >> ----- >> You received this message because you are a member of the Vintage Macs >> group. >> The list FAQ is at http://lowendmac.com/lists/ vintagemacs.shtml >> <http://lowendmac.com/lists/vintagemacs.shtml> and our netiquette guide >> is at http://www.lowendmac.com/ lists/netiquette.shtml >> <http://www.lowendmac.com/lists/netiquette.shtml> >> To post to this group, send email to vintag...@googlegroups.com >> To 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