View Single Post

Early_S_Man
Early_S_Man is offline
Registered
 
Early_S_Man's Avatar
 
Join Date: Dec 1999
Location: TX USA
Posts: 9,804
Send a message via Yahoo to Early_S_Man
Steve,

Just ran accross this thread, again, during a search ... hopefully you haven't given up on the repair and thrown out the two dead Speed Switch units!!!

The schematic I posted on other threads is the same for all of the 1969 and later Speed Switches [aka RPM Transducer/Speed Relay] regardless of the application on carbed or MFI engines ... just the values of C4, R5, and R6 changed!

D7 and D8 [your device #1] are both protection devices or surge suppressors of the MOV, SIDACtor or bidirectional Transzorb type ... here are a couple of comprehensive databooks that can be downloaded:

http://www.onsemi.com/PowerSolutions/search.do?searchString=DL150-D.pdf&searchType=others&tabbed=Y&clearFilters=Y

http://www.littlefuse.com/cgi-bin/r.cgi/en/allsearch.html?DoSearch=Y&WhichDB=&textfield=sidactor+databook

Even though I don't have a part number or specs for D7 or D8 [haven't put one on a curve tracer, yet] ... it is safe to say that around 15 - 16 Volts is the effective range they need to be in to protect the 16 Volt capacitors from blowing up when transients occur with a failing alternator!

Your device #2 is T2, a Siemens BCY45-IX transistor, no longer available, except for NOS parts (new old stock) that can be replaced by a 2N2222A transistor [selected for hFe > 200] or 2N5088 transistor.
__________________
Warren Hall, Jr.

1973 911S Targa ... 'Annie'
1968 340S Barracuda ... 'Rolling Thunder'
Old 02-03-2006, 04:50 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #8 (permalink)