Urei 1176 Rev. D - ? defective Power Transformer?

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matthias

Well-known member
Joined
Jun 4, 2004
Messages
768
Location
germany / frankfurt
Hello,

I currently have an old Urei 1176 Revision D Limiter on my bench.

At first I thought the voltage is a bit off (28V instead of 30V)
but when I inserted some new light bulbs, the power dropped to 25V after the regulating zener diode.

I disconnected the 3 wires from the transformer and measured 32 V AC (unloaded) on each secondary winding. I assume this is too low. The input voltage is 230V AC (schematic says 240V , btw)

is this a normal behaviour, maybe because the input voltage is too low, or do you think the transformer is defective and I should use another one...


thanks,
matthias

revdpsu.JPG


psu.JPG
 
The secondary voltage should be approx. 60V center-tapped:
(red1 - yellow/red ---- 30V, red/yellow - red2 ---- 30V,
red1 - red2 ---- 60V).
 
yes, of course I measured from center to each secondary...

but as I said I measure 32V AC unloaded and with a load I only get something around 25V dc after the rectifier diode... when I disconnect the lamps it is 28V wich is still too low...
 
What is the secondary voltage (AC) when the lamps are connected?
Could you measure the ripple voltage on C23 using a 'scope or DVM set to AC?
 
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