O.K. Thanx for all the responses. The circuit board has a label
" Z 1" where this small glass cylinder is and under it is what looks
like a symbol for a zener diode. Now I am wondering two things - how
do you test a zener diode and how can you tell what value it is for
replacement. The board also has " 4V7" next to the diode symbol and
with a magnifier I can see " C4V7" and "CH" on the diode itself.
Also the glass cylinder sort of looks cracked, but it is hard to tell.
Thanx again, Brett