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Post by tvtechrich on Sept 12, 2024 12:56:10 GMT
I know at one time I would hold the stop relay in, and The lamp would stay on until the hammer hit. But it didn't seem to make a difference . I will check again when my new bulb comes.
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Post by tvtechrich on Sept 12, 2024 20:49:15 GMT
So I got my wife to enter song while I watched the write relay and it does latch down until the keys pop out. So, thinking that the -28 supply might be pulling down when asked to supply a pulse, I tied a 2200uf cap across it. And the cap blew apart. I'm getting between 52 and 40volts, depending on load. That's if I connected to the right pin on the socket . Resistance tells me it connects to the fuse holder.
I see no schematic showing how it arrives at -28v. Also I'm used to being able to trace wires through plug and socket pins like P9 to J9 red/white. Did rockola forgo this or did I miss something ? Power supply schematic other than the one in the amp print? My old teachers said 90%of your repairs will be power supply related. I have found that to be true. Thanks for your continued help.
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Post by tvtechrich on Sept 12, 2024 20:50:08 GMT
2200 @35v
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Post by jukenorman on Sept 13, 2024 8:54:56 GMT
The original documentation as supplied by Rock-Ola included a large fold-out schematic of the complete machine and this had the diagram of the power supply. The power supply is very simple so in most cases it is not missed. Copies of the large schematic are available eg Jukebox World in Germany. I will message you a copy of the 436 power supply, it's probably identical but if not, close enough to work with.
Back to your last post - it's not the write-in relay we're concerned about but the stop relay. When the stop relay energises, it stays energised until the write-in relay drops out. The stop relay directly energises the wobble plate solenoid through one of its contacts. The stop relay also initiates the operation of the write-in hammer solenoid but the operation of it is a bit more convoluted. I suspect that when the issue with the wobble plate solenoid is resolved, the hammer coil will then work (otherwise there is more than one fault).
The power supply DC is unregulated, it will read about 50V when there is no load. Unfortunately I cannot see what is happening and the "wrong" current limiting lamp might be a distraction but I just can't understand why, with the write-in motor running, the wobble switch solenoid doesn't energisee when you manually operate the stop relay. Indeed the wobble plate solenoid should energise even if the wrte-in motor isn't running when you operate the stop relay manually (although the stop relay wouldn't self hold)!
Norman.
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Post by tvtechrich on Sept 13, 2024 14:08:12 GMT
I did get the proper bulb but it made no difference . Thanks for pointing out that it's the stop relay . I hooked a speaker to the wobble solenoid so I could hear the pulse, but no way to measure amplitude or duration. I'll see if The stop is latching. It must not, as the bulb flash is instantaneous .
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Post by jukenorman on Sept 13, 2024 16:47:49 GMT
There's something bugging me about your problem - I cannot understand how the pushbuttons are unlatching. I'm beginning to wonder whether you have a short somewhere and when the stop relay operates, something is pulling down the AC voltage (and possibly also the DC voltage?) causing the latch solenoid to drop out. And of course, the capacitor that you connected across the write-in relay blew up because that's an AC relay LOL!
Norman.
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Post by tvtechrich on Sept 15, 2024 13:31:32 GMT
Thanks for the power info. Did you notice that they drew the diodes backwards for the bridge rectifier ? The way they are drawn the 50v supply would be positive not neg. My wife's mother broke her hip and we had to go 200 miles to the hospital yesterday so I haven't had a chance to troubleshoot since I talked to you. Today I'll get someone to input a song while I manually hold the stop relay down. So close to working ..always finds the right song lever, brakes the write in motor, pulses the wobble solenoid and hammer .Just not hard enough to set the lever. If I have to I'll rig up a pulse stretcher with a separate power supply and see how that affects it.
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Post by jukenorman on Sept 16, 2024 21:11:16 GMT
I am away for two weeks. I probably won't have much time for the forum, I won't have access to any documentation but I hope to see full progress here before I return! Sorry to read about your mother-in-law, I hope she makes a speedy recovery.
Norman.
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Post by tvtechrich on Sept 18, 2024 16:33:52 GMT
She died this morning .But she was ready .Still sad tho.
On my jukebox I kept finding it over the proper lever, but not tripping it. So I hooked up a power source and 1 coil works fine. Other pegged the amp hand and didn't pull. Yay , right? 3 or 4 times. So I undid the black tape to follow the wires to be sure which was bad..then both work now! No bad insulation that I could find. So in trying again I find all A selection work 1-8. Bs only work if I hold in the B button. Broken slide and contacts in selector. Tried jumpering out to see if the other letter would work , but it scrambled my output. Don't know if it pays to go on. Have too see if the selector assy is available . Looks tough to replace contacts individually .
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