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Post by paradisecs on Sept 19, 2018 15:56:58 GMT
Do the lamp circuits need the power draw of the incandescent bulbs for the circuits to work correctly or can you replace them with LEDs? The fluorescents are easy but not sure of all the others.
Stephen
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Post by Ron Rich on Sept 19, 2018 17:15:56 GMT
Hi Stephen,
The "Select section" wedge lamps, MUST be either, #656, #650, or # 152 as outlined in various places, including my "Seeburg MicroLog Trouble Shooting Guide"--Use NO other there !! Only other "lamps" are used for the "Selection Now Playing display"--these are # 19 bi pin type--I see someone offering LED replacements at astronomical $$$ --have not tried them, but they probably will work, as they are NOT transistor driven (See your schematic) Ron Rich
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Post by paradisecs on Sept 19, 2018 19:21:19 GMT
Thanks. I thought that was the case but I wanted confirmation. I saw a batch of 656 online that said they were LED but was pretty certain they wouldn't work.
Stephen
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Post by Ron Rich on Sept 19, 2018 19:29:37 GMT
Stephen,
What was the price per lamp ? I have not seen any "advertised" to be 656, wedge type--yet- IF, reasonably priced, I could try them on an extended test, to see if any harm is done to the drier circuit---
Ron Rich
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Post by paradisecs on Sept 19, 2018 20:12:46 GMT
I'll send you a private message. I don't want to post a link to something that could ruin someones equipment.
Stephen
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Post by Ron Rich on Sept 19, 2018 20:16:40 GMT
Stephen,
What was the price per lamp ? I have not seen any "advertised" to be 656, wedge type--yet- IF, reasonably priced, I could try them on an extended test, to see if any harm is done to the driver circuit---
Ron Rich
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Post by paradisecs on Sept 19, 2018 20:44:55 GMT
Depending on where they were listed, as low as $1 a piece. Still seems high. I sent you the links.
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Post by robnyc on Sept 19, 2018 23:10:51 GMT
Stephen, in these transistor switched circuits you can use leds but you will have to experiment with a value of current limiting resistor for the led. I do this in all cases where existing low current bulbs are used, such as "Stereo" tuning indicators and logic tally lights.
Since the source voltage is in the mid-upper 20's. Since the led w/series resistor will draw a lot less than a filament bulb I start out with a 10k pot set at full resistance and bring it down to the point where I measure about 2 volts across the led. Most leds are rated @ 3.3vdc -but generally, less is more than enough in these direct view applications.
RobNYC
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Post by paradisecs on Sept 21, 2018 14:59:54 GMT
Thanks for the info. I'm not ready to try that yet but I'll get to it eventually. What is it that can/will go wrong if using the wrong bulbs? Ron mentioned the driver circuit but what actually happens or what theoretically could happen?
Stephen
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Post by Ron Rich on Sept 21, 2018 16:01:38 GMT
Stephen,
A lot depends on the design of the circuit-- On the Seeburg "black boxes" using the wrong # lamp usually takes out one, or both of, the transistors that drive the lamps--It CAN, and once in awhile, does worse ! In the "Red Box" design--no problem--lamp may or may not light, but usually nothing is harmed, as this was a later design, and the gent ( the late, great, Tony Miller), who designed it, was very familiar with the poor design of the black box in this area. Ron Rich
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Post by paradisecs on Sept 21, 2018 16:38:16 GMT
Is that because it doesn't draw enough of the current from the transistor so it overloads? I'll have to read up in Tony's Black Box book more on this circuit.
Stephen
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Post by Ron Rich on Sept 21, 2018 16:54:28 GMT
Stephen,
No--it's the opposite--looks like a short to the transistors--often takes out the series resistor at the lamp socket too-- draws too much -- Ron Rich
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