Tape Project Forum
Tape Machines => Tape Project Machines => Topic started by: stellavox on December 17, 2009, 09:40:19 AM
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When I took my unit apart to work on a few issues I also investigated the burnt out VU meter lamp situation. Each bulb looks like a very small (diameter) fuse with a lead coming out each end. Both bulbs are connected in parallel and attach to a tap on the 12 volt (center tapped) power transformer winding. I did NOT think to measure the AC voltage going to the bulbs but it will be LESS that 12V. I unsoldered one side of the good bulb so both of mine are now dark.
MCM electronics sells bulbs which look like they will work just fine - in fact the catalog describes them as "level meter lamps". They are available in 3 voltages 6.3V(AC)-Order #25-445, 8V-Order #25-450 and 12V-Order #25-455. Each cost around 60 cents. Absent measuring the actual voltage you could probably get by with the 8V units but I'd try the 12V ones - if they are bright enough, they will probably last much longer.
Charles
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I seem to remember someone replacing the VU bulbs with led's. I did have a pair of replacement bulbs for mine but I'll be damned if I can remember where I put them! I think the guy that used leds did that in an Otari. I figure any long lasting light would work as long as they fit.
From working on the Dolby units, I'm shocked at how long some of these little bulbs last! I think that out of all the units I've bought, only one bulb has died of natural causes (I've shorted out the power supply a couple of times and taken out any that were on). I figure that since these units were all rack mounted in a duplication facility or radio station and there's no power switch, they were probably almost never turned off.
Here's a good source for unusual bulbs (thanks Harold!).
http://www.bulbtronics.com/default.aspx