DL7VHF placed the FT-736R SMPS schematic diagram on Last Pages http://www.catlog.net/_Descarregas/Manuals/03-Yaesu/Yaesu%20FT-736R-PS-Repai...
SCR21 : marked: TH21 5P4M NEC 5P4M, 5A, 400V Thyristor in a TO-220 case, == Possible substitutes: Phillips BT258-500R , STMicroelectronics TYN608 https://www.digikey.com/products/en/discrete-semiconductor-products/thyristo...
NTE 5424 appears to be suitable substitute. https://www.nteinc.com/specs/5400to5499/pdf/nte5424.pdf
Digi-Key F7250-ND (Littlefuse S4008LTP) SCR 400V, 8A Standard Recovery, TO-220AB-L, Isolated Tab https://www.digikey.com/product-detail/en/littelfuse-inc/S4008LTP/F7250-ND/5... Littlefuse Data Sheet https://www.littelfuse.com/~/media/electronics/datasheets/switching_thyristo...
greg w9gb === Date: Fri, 07 Aug 2020 16:04:16 -0600 From: "Vince Fiscus, KB7ADL" [email protected] To: AMSAT-BB Subject: [amsat-bb] FT-736 power supply part
Hi All,
I walked into the shack about a month ago and smelled something really hot like the smell from a hot resistor. Turned off all the equipment waited a while then turned everything back on.
The FT-736 didn't come back on, so I assumed the power supply, as this is a common problem with the rigs as they get older.
Bought a repair replacement kit for the electrolytic caps in the power supply, which is normally the problem. They get baked and fail.
Got the power supply out last night to do the repairs and I discovered it was the SCR in the power supply that had totally burned up. Weird.
Does anyone here have or know a Digi-key or Mouser part number for the SCR or an equivalent compatible part? It labeled SCR21 on P.C. board.
Thanks Vince