Granada Television Brochure, 1970s
Long Gone UK TV Shops
Memories of a Derwent Field Service Engineer
PYE Australia Circa 1971
Radios-TV VRAT
Fabulous Fablon
Thorn TX10 Chassis
Crusty-TV Museum, Analogue TV Network
Philips N1500 Warning!
Rumbelows
Thorn EMI Advertising
Thorn’s Guide to Servicing a VCR
Ferguson 3V24 De-Robed
Want to tell us a story?
Video Circuits V15 – Tripler Tester
Thorn Chassis Guide
Remove Teletext Lines & VCR Problems
Ceefax (Teletext)
Suggestions
Website Refresh
Colour TV Brochures
1970s Lounge Recreation
CrustyTV Vintage Television Museum
Linda Lovelace Experience
Humbars on a Sony KV2702
1972 Ultra 6713
D|E|R Service “The Best”
The one that got away
Technical information
The Line Output Stage
The map
Tales of a newly qualified young engineer.
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Sanyo SMD
Disastrous Company Rebranding
1969 Philips G22K511
Memories Of The TV Trade
Crazy house
Dirty TV screens
Dual Standard and Single Standard CTV’s
Radios-TV on YouTube
The Winter of 62/63
A domestic audio installation
1979 Ferguson Videostar Deluxe 3V16
Music centre modifications
Unusual record player modification
B&K 467 Adapters
Mishaps In The Trade
1971 Beovision 3200
1971 Bush CTV1120
Granada Television Brochure, 1970s
Long Gone UK TV Shops
Memories of a Derwent Field Service Engineer
PYE Australia Circa 1971
Radios-TV VRAT
Fabulous Fablon
Thorn TX10 Chassis
Crusty-TV Museum, Analogue TV Network
Philips N1500 Warning!
Rumbelows
Thorn EMI Advertising
Thorn’s Guide to Servicing a VCR
Ferguson 3V24 De-Robed
Want to tell us a story?
Video Circuits V15 – Tripler Tester
Thorn Chassis Guide
Remove Teletext Lines & VCR Problems
Ceefax (Teletext)
Suggestions
Website Refresh
Colour TV Brochures
1970s Lounge Recreation
CrustyTV Vintage Television Museum
Linda Lovelace Experience
Humbars on a Sony KV2702
1972 Ultra 6713
D|E|R Service “The Best”
The one that got away
Technical information
The Line Output Stage
The map
Tales of a newly qualified young engineer.
Tales of a Radio Rentals Van Boy
Sanyo SMD
Disastrous Company Rebranding
1969 Philips G22K511
Memories Of The TV Trade
Crazy house
Dirty TV screens
Dual Standard and Single Standard CTV’s
Radios-TV on YouTube
The Winter of 62/63
A domestic audio installation
1979 Ferguson Videostar Deluxe 3V16
Music centre modifications
Unusual record player modification
B&K 467 Adapters
Mishaps In The Trade
1971 Beovision 3200
1971 Bush CTV1120
Surface mount SOT-23 transistor help please
My Fluke has been great since replacing the faulty LCD display but the backlight has never worked, trivial I know but curiosity got the better of me today and I took a look.
Tracing back from the led brought me to a couple of transistors one leg of which was broken from its track, brilliant I thought and soldered it back. No such luck.
Opening it again I tested the transistor this time and found it was open circuit on the collector leg when testing all directions.
Would any expert out there be able to tell me what it is and what I can replace it with please
Thanks Jeffrey, I had thought about checking out some scrap boards to implement that idea although the more modern boards seem to have escaped the transistors in the design stage and skipped straight to a socking great IC
I don't quite understand the design of that circuit, looking at your picture, the top pins are the collector usually, lower left is emitter and lower right is base.
By the looks of it, the collector of the top goes through a Via, top left, then the Emitter of that one goes to the collector of the next. The emitter of which must go through the board underneath the device.
The bases of both are fed from the same signal via the 2x resistors to the right. It's not like a Darlington pair.
It looks like sort of a totem-pole output with 2x of the same devices. Can't figure out why.
Try just shorting out the defective device, maybe it will start working.
https://sites.google.com/site/davegsm82/projects/radioputer - A BC5441 Turned into a Media Centre PC.
Measuring on the bottom left pin of upper transistor and toggling the backlight gives 1.5 volts which is switched from the transistor below. The resistors trace up to two more transistors, when measuring here whilst toggling turns 5 volts on and off.
I have not thought much on this yet and its back together for the time being to stop childs fingers getting to it.
It did make me think that the controller also has access to the backlight so it could be to do with that for auto backlight power off.
I would put a scope on there.
It could be some kind of chopper circuit to step up or down to drive the back light.
Ok, will try that when children are offline
Squinting at your picture I think I make the marking as 1R, which, according to Mr Towers equates to an MMBT2059 NPN Transistor. SOT23 case and same as conventional type 2N5089.
My perception is my reality.
Thanks Dave,
Quite by chance I hit this site a few mins ago that lists the actual device as:
1R MMBT5089 Mot N SOT23 MPSA18 Vce 25V
http://www.marsport.org.uk/smd/mainframe.htm
Along the lines of what Jeffrey said something like a BC848A should be fine
That is a good site.
Cheers
https://groups.yahoo.com/neo/groups/Fluke_DMM/info
You have to join this group. They may be able to help.
Al
equates to an MMBT2059 NPN Transistor./quote]
Glad you got it sorted..hope you weren't put off by my typo!!! I must read what I write! 2059 of course should say 5089
My perception is my reality.
All working fine now, the first transistor I pulled off a computer motherboard checked out ok, so in it went. Could do with some IPA on a cotton bud to remove the flux but I am out.
Thanks for the help
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