HP16500 ABC Sony CRT - Page 1
Forum section: electronics / testgear

author: AllTheGearNoIdea
author_rank: Unknown
timestamp: October 05, 2017, 11:07:45 pm
content: Hi a few of you may remember my video about the HP16500C I bought from the states that arrived with the neck of the CRT smashed. Well always wanting that bit more pain I bought another one spares or repair. Well the condition of the spare unit is like new inside and very clean but annoyingly it has a dead CRT module. It not physically damaged just not working.I have the service and maintenance manual but they do not contain any schematic it likely the crt section was a replacement only unit. The crt module is made by Sony does anyone have any information or schematic please. I have tried searching A B C models as they share the same CRT module with no luck.I may just swap out the tube with the tube in the first unit that was necked. But the spares unit is i such good condition it would be worth attempting repairs first.Apart from checking the supply voltage and the video sync pulses from the main board I’m at a bit of a loss now. I know the various risks working with CRTs and have restored quite a few old valve televisions but don’t claim to know how they actually work. I think without circuit diagram I’m going to be a bit stuck.Can anyone provide any info or suggest we’re to start debugging the crt module. Regarding the LOPT and double/tripler I’m not hearing or smelling HT - you know what I mean.Regards Chrishttps://youtu.be/L97pajQgxXg

author: stj
author_rank: Super Contributor
timestamp: October 06, 2017, 06:12:13 am
content: failure points on a monitor are the horizontal deflection i.c. and the line-output transistor and transformer.that's where you begin - although that's not strickly true, because you first check for broken soldering on anything heavy or fitted to a heatsink or other potential source of leverage.

author: AllTheGearNoIdea
author_rank: Unknown
timestamp: October 06, 2017, 12:30:19 pm
content: I think thats good advice thanks. Maybe if I can identify the chip set etc I will be able to find something simiar to work with. In essense this is just a small computer monitor made by sony. it takes 120Vdc in and various TTL level video sync signals in a self contained module.Will everthing on the PCB be relatively low voltage 100-250V range. I guess im talking about the connections to the electron guns at the back of the tube connector and the primary side of the lopt. I assume its just the output from the LOPT and Doubler and Anode connection I need to bevery careful about. I have equipment that will meassure the LOPT output and am aware of discharging the tube but I have never removed an anode cap or discharged a CRT tube before so im a bit unsure.As I said I dont hear anything and you normally get a bit of sound when a CRT power up from the HT. I did not explain very well in my first post but the monitor is total unresponsive and dead. Does nothing at all nothing on the screen. I have just checked that we have 120V power to the board and video signal inputs. The degauss control is also inactive.Note: Im pretty familiar with HV and work with 25KV at perspective fault currents of 2000KA, but i dont normal have it on the bench and I have never been very interrested in repairing TVs until now. So Im open to tips from all you TV guys.Many Thanks Regards ChrisModify message

author: stj
author_rank: Super Contributor
timestamp: October 06, 2017, 01:44:55 pm
content: the main supply to the line output transformer, usually refered to as B+ is going to be in the region of 60-120v dcthe line output transformer is generating the main HT on the anode, plus the focus voltage and some other painfull voltages that DO go to the tube base.so dont touch the tube neckboard/connector etc.post a bunch of foto's of the monitor.

author: AllTheGearNoIdea
author_rank: Unknown
timestamp: October 07, 2017, 07:35:01 pm
content: I have found out the monitor is a Sony CHM-9001-00. But not found any service data as yet

author: AllTheGearNoIdea
author_rank: Unknown
timestamp: October 08, 2017, 07:47:53 am
content: Here’s is my first look at the CRT unit with the Broken tube my next step will be to try and get some more detailed measurement. Not sure if I should just try changing the CRT or if the will lead to problems aligning the tube in a new chassishttps://youtu.be/BEUu90NVBws