[Amps] 8877 date codes

[Dan]

A quick archive search for 8877 bad date codes found all sorts of 
information. One post by G3RZP seems to have a good summary of the 
problem. Here it is:

"Here's a copy of what I was sent on the subject: It includes some infor from 
Dick at ETO


>/Here is the 8877 info. Looks like you want to avoid 8877's with a date/
>/code anytime frm 1986-1988./
>/For those who expressed interest and/or skepticism about the issue,/
>/here's a reasonably accurate time line of events from our QA records./
>/Eimac puts 8877 heat dam design change into production -- ~08/86/
>/ (Completely unknown to us at the time)/
>/First identified tube failure at MRI end-customer field site -- 12/86/
>/First suspect tube routed back to Eimac via ETO -- 01/87/
>/Meeting with Eimac -- 05/87/
>/FIrst fix devised by Eimac; second meeting w/Eimac -- 07/87/
>/Third & fourth meeting with Eimac -- 08/87/
>/Initial Eimac delivery of "fixed" 8877's -- 09/97/
>/Delivery of "fixed" 8877's to customers -- 10/87/
>/Problem re-surfaces @ field customer(s) -- 03/88/
>/FIfth meeting with Eimac --/
05/88
>/Second fix devised by Eimac -- 06/88/
>/Initial Eimac delivery of 8877's with second "fix" -- 08/88/
>/Delivery of "2nd fix" 8877's to MRI customers -- 09/88/
>/Completion of field upgrade with replacement tubes -- 05/89/
>/** NOTE: Because tube date codes approximate/
>/ shipping rather than manufacture dates,/
>/ they may vary ~1-3 months from the/
>/ event dates given above./
>/Largest MRI RF amplifier manufacturer's record/
>/of 8877 usage by year:/
>/ In new amps As replacements/
>/ almost 100% due to/
>/ heat dam/g-k shorts/
>/1987 500 575/
>/1988 650 1600/
>/1989 500 550/


73

Peter G3RZP"

73, Dan, N5AR