CRT Philips CGA/EGA repair help 9CM073/00B - Page 1
Forum section: electronics / repair

author: OriginalDan
author_rank: Contributor
timestamp: August 27, 2023, 12:43:01 pm
content: gday got this monitor recently upon inspection two parts had some corrosion, attached the main relevant images but because of the fourm limit heres analbum of more imageslooks like whatever glue was on the inductor caused it, I'm still quite the noob butin the service manualit says the part being a 200uH inductor but no other information, none of the numbers on it gave any useful google results, i thought the ohm or amp rating would matter a lot on the replacement part?the 2nd part was a transistor that had little bits of corrosion so might as well replace that too thankfully the model num shows results: PH BDT51 so thats easy to replace but I'm not so sure about the inductorseems this is a live chassis design ill have to be extra careful if we can find the part and get it running, also one of the ground leads just broke off very easily so i might replace all of those ground wires as they look sketchy as hell, I've read others claim philips would have dodgy factory jointsis there a recommended insulated wire guage for this? the originals are just bare wire with some plastic tubingalso anyone know how to hook up cga/ega crts to a modern system? if we can get it running could run a colour test suite through it as i picked up a colour calibration tool recently, specifically a spyder2 though i might get a more modern one for my lcds and it seems some models can still calibrate crtsappears these monitors might have been packaged with an XT clone possibly the Philips NMS 9100 or similarany help is greatly appreciatedalbum of more imagesservice manual

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: August 27, 2023, 08:40:01 pm
content: As far as the inductor goes, if it measures anything near 200 uH, it should be OK. Do not clean it with solvents, You might dissolve the coating. Just clean it with soap and water. You can take it apart and rewind. You can revarnish the wire if necessary, if you take it off carefully.This is time consuming but so is looking for another part that will fit.

author: OriginalDan
author_rank: Contributor
timestamp: August 28, 2023, 03:36:45 am
content: Quote from: Wallace Gasiewicz on August 27, 2023, 08:40:01 pmoh great point i dunno why i didnt think to look up to measure it first, good thing i got an lcr meter for caps, i dunno what frequency to test it at but seems its all around 200, as you suggest probably best to take it apart and rewind as a basic clean might not get everything underneath it and could cause it to corrode again later, I've got some spare enameled copper wire for a future project (seeing if i can convert some small crts into vectors by rewiring the yoke)so i may just take the wire off, clean up the holder with solvents then put new enameled wire on it since taking it all apart id need to rewire anyway might as well use new wirea simple diode check on the npn transistor shows voltage drop so i hope it's still fully working, the cheapest original philips bdt61 i could find was $45! there are cheaper BDT61C$18aud for 2 but on the datasheet the C version collector base voltage is 120v instead of 60v so I'm not sure that would be a compatible replacement?the original looks undamaged enough to work provided the corrison isnt internali do have a spare amiga500 i should be able to get that going to atleast test the crt if the rewiring works though i might need to wire up a custom 9pin for itill look up how to wire my own inductor and report back on how it goes thanks.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: August 30, 2023, 01:28:20 pm
content: Transistor is just a higher voltage, high watt NPN and there are many alternatives:https://www.web-bcs.com/valsearch/transistor/JJKDCKBGHKBB/1693401772_1_1.php?force=Should be really cheap.Probably the most important thing is to heat sink it well.

author: OriginalDan
author_rank: Contributor
timestamp: September 15, 2023, 03:40:42 am
content: Quote from: Wallace Gasiewicz on August 30, 2023, 01:28:20 pmthanks i tried ordering an original before i saw this comment and was waiting for it to arrive only for it to be cancelled due to no stock lol, your link seems to error out on my end with a 'the requested document was not found at this location' message? is there a compatible one that would work for the BDT61 transistor?still trying to figure out how id hook it up to a modern system to use a colorimeter on it, best bet might be thisthis arduino projectbut ill keep looking