Identify component on TDK CCFL inverter - Page 1
Forum section: electronics / repair

author: bdunham7
author_rank: Super Contributor
timestamp: August 14, 2020, 06:20:19 pm
content: I have a TDK CXA-L0605-VJL CCFL inverter board from a R&S CMU200 that I'm repairing. I've already ordered a new/used/refurb board but it won't be here for a while and if I can fix this one, I'd like to.The problem appears to be the component marked '20' in the photo. Bypassing it allows the board to work and it appears to function OK. I'm assuming this is an SMT fuse or PTC device, but I'm not sure which. I was unable to locate that code for any device that made sense.If I repair the board, I want to use the correct device, not the small wire strand I have bodged across it right now. The device draws about 950mA in operation, so I'm assuming this is a 2A or so device. It is 1210 size. Does anyone know exactly what it is?

author: bdunham7
author_rank: Super Contributor
timestamp: August 14, 2020, 07:18:38 pm
content: OK, I found it. It is a KOA CCP2E20. This is a 1210 fast-blow fuse with a 2Afusing current(blows in 1s) and an 800mA continuous current rating. IMO, that's problematic for a unit that draws 950mA in normal operation, so I will put in a 1.25A replacement with a 2.5A fusing current. I'll leave the post up since a lot of people here have CMU200s. If you have a dark screen, order a fuse before you go to all the trouble of tearing it apart because I'm betting I'm not the only one.

author: shakalnokturn
author_rank: Super Contributor
timestamp: August 14, 2020, 10:33:14 pm
content: Is it possible that the 950mA arn't normal operation?Could be caused by transformer insulation breakdown, leaky ceramic cap on secondary, PCB or wire insulation breakdown.I've seen breakdown of heatshrink sleeving over the ends of the CCFL's before in other equipment.

author: bdunham7
author_rank: Super Contributor
timestamp: August 14, 2020, 10:54:43 pm
content: Quote from: shakalnokturn on August 14, 2020, 10:33:14 pmThe inverter board is an off-the-shelf unit used in a specific application. I have two different data sheets for the unit--one says typical 700mA, max 800mA but the second says typical 800mA and max 1000mA. I have no information about the normal current draw for the specific application (CCFL type) so it is possible that the unit is just run near its maximum in this application. It seems to work fine and I'm giving it a long burn-in test. However, even if you go by the first data sheet, running a fuse at 100% of its continuous current rating is just pushing the limits a bit too much, IMO, unless you really need a low fusing limit. In this case, I don't think there's any need for an extremely low current fuse as the circuit is driven off of essentially a PC power supply.

author: KenPaisley
author_rank: Newbie
timestamp: October 23, 2020, 02:01:58 am
content: CFL tube and what appears to be genuine TDK inverter is available on Amazon. My display is very bright now. Don't bother with the inverters on eBay. They work, but display is dim. $50 for the inverter and $22 for the lamp.

author: bdunham7
author_rank: Super Contributor
timestamp: October 23, 2020, 02:13:57 am
content: Do you have a link for the CCFL tube?

author: KenPaisley
author_rank: Newbie
timestamp: October 23, 2020, 02:18:58 am
content: https://www.amazon.com/gp/product/B07L4Z6N3X/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1My other cmu200 I had to recap the motherboard and the made the screen brighter than it was, but I ordered another cfl tube. Hope that link works.

author: KenPaisley
author_rank: Newbie
timestamp: October 23, 2020, 02:24:58 am
content: https://www.amazon.com/gp/product/B08B3G9SMH/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1Took a while to get but worth the wait. I have two cmu200s.