18-09-2023, 07:52 PM
(This post was last modified: 18-09-2023, 07:59 PM by Mike Watterson.)
"So what's wrong with all those perfectly ordinary plastic case transistors?"
Mounting stress. Holes don't match preforming, or lead preforming stress it or auto insertion stress. It's just more common with badly mounted Lokfit. I'd suggest stress related non-Lokfit plastic case transistor failure is more common in low volume hand assembled gear than mass produced with preformed leads that's auto-inserted.
The only non-Lokfit plastic transistors I've had to replace in mass production items were all VHF RF preamps or VHF front-end mixer-oscillators. That's more common with mains gear that uses a separate aerial, which isn't surprising.
Oh, and a few high voltage parts (TV Video drive and TO92 used in SMPSU/Electronic ballast etc). Hardly a surprise.
Mounting stress. Holes don't match preforming, or lead preforming stress it or auto insertion stress. It's just more common with badly mounted Lokfit. I'd suggest stress related non-Lokfit plastic case transistor failure is more common in low volume hand assembled gear than mass produced with preformed leads that's auto-inserted.
The only non-Lokfit plastic transistors I've had to replace in mass production items were all VHF RF preamps or VHF front-end mixer-oscillators. That's more common with mains gear that uses a separate aerial, which isn't surprising.
Oh, and a few high voltage parts (TV Video drive and TO92 used in SMPSU/Electronic ballast etc). Hardly a surprise.
