Touchmaster TM4 sound problem?

08slicktop

Member
Jan 6, 2016
26
Canada
I have a touchmaster tm4 that seems to function completely, other than the fact the siren is EXTREMELY quiet. Almost whisper quiet. I've tried multiple speakers and still no positive result. I'm not too familiar with these sirens. Anyone know what might cause them to not put out sound to full volume? Thanks!
 

shues

Lifetime VIP Donor
May 21, 2010
10,276
NW Indiana
There is an profoundly thorough technical manual available here: https://www.fedsig.com/resource-document/file/7424

I would start by replacing both of the final output transistors, listed as Q8 and Q9 in the schematic, with brand new parts. They are listed as 125N40 transistors.

A quick search lists a few possible substitutes:
2SK1258, 2SK1379, 2SK1422, 2SK2121

Source: http://pinout.net/element_browse.php?conid=60108

If you are unfamiliar with doing this sort of work youreself, member MtnMan may be able to help: https://elightbars.org/forums/members/mtnman.21452/
 
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