CRT and power supply replacements? - Page 1
Forum section: electronics / repair

author: rea5245
author_rank: Frequent Contributor
timestamp: May 08, 2020, 03:10:02 pm
content: Hi,I have an old instrument with a faulty power supply. As I was struggling to get it out of the case, a wire snagged on it, pulled at the CRT's connector and cracked the seal. F---!So assuming I still think it's worth repairing this (I'm starting to wonder) I need to find two equivalent parts.The CRT is labelled as a Panasonic 310K3BG1N. Looking on eBay, I see that doesn't even match Panasonic's numbering scheme, which seems to always start with two letters. Can anyone help me find an equivalent CRT?The power supply, OTOH, looks somewhat standardized. The model number is OFSX-225IEC, but looking on eBay I see that there were a lot of different parts with that model number, and they all have different voltage and current outputs. Mine is a 0950-1762 which has 5V@30A, 30V@1.5A, -12V@4A, 12V@5A, and then an output labelled "P.F.". I don't know what that means.eBay has a few of this model, but none matching the specific part. Again, any advice?Thank you,Bob

author: CaptDon
author_rank: Super Contributor
timestamp: May 08, 2020, 05:20:40 pm
content: What kind of unit are these items in, you never said. The '310' denotes the sizeof the CRT, the G1 is the same as P1 in most cases I have seen which is an oldstyle green oscilloscope phosphor (today replaced with p31 which is brighter) andI would think you will be able to find some suitable replacement, maybe from ajunked unit on Ebay similar to yours? I think the 310 is the diagonal measurementof screen size in millimeters? I think some of the radars I have serviced had '310'sized green screen displays, I may even have a spare, I'll look this weekend.

author: rea5245
author_rank: Frequent Contributor
timestamp: May 08, 2020, 06:42:24 pm
content: Quote from: CaptDon on May 08, 2020, 05:20:40 pmIt's a Hewlett-Packard 78560A central station for use in a hospital cardiac care unit. It's completely useless today. It's only value to me is that I worked on as my first job out of college, so it would've been nice nostalgia to get it working again.- Bob

author: bob91343
author_rank: Super Contributor
timestamp: May 08, 2020, 07:01:01 pm
content: I suspect the PF terminals are not an output, but a place to connect a component to increase the power factor on the power line. Many power supplies fall down in meeting power factor requirements and may need help.Power factor is the ratio of power drawn from the line to volt-amperes. In other words, the input current may not only be higher than computed from power requirements but also not be in phase with the supply voltage. The power company frowns on low power factors and further, they require heavier conductors to handle the excess current.

author: CaptDon
author_rank: Super Contributor
timestamp: May 08, 2020, 09:21:11 pm
content: I never messed with the HP stuff, didn't even know they had BioMedicalofferings until I saw some of the HP stuff in a BioMed class at Erie TechnicalInstitute BMET course. I worked in O.R. BioMed in York Pa and we had about90% SpaceLabs gear and some G.E. Marquette and a few other oddballs.I have a SpaceLabs patient monitor at home (Big color unit like the B&Wone but without the module buckets) but forget what model number. Stillworks great, Adult NIBP, SP02, Temp1, Temp2, Resp and ECG all in color!!I was already a BioMed Tech1, but stopped in at E.T.I. just to check them out.Wasn't impressed!!!!