Rock-ola 477 Max random play, no play, etc.

[prime]

Hi Norman, i just read what it is and will pick one up, if you can direct me where to test i would appreciate it. pete

[Ron Rich]

Pete,
Never "hate to admit' anything-- that's how we learn-- "Goggle it"-- They are under $10.00 and are very useful for telling what state an"electronic switch" is in -- I just replaced my 40 some year old one, a few months ago-- my dog ate it-- Ron Rich

[jukenorman]

Hi Pete,
If I have followed you correctly, you can operate the pushbuttons OK and insert the three digits to make a selection - in which case, look at sequence 9. The narrative tells you where you should be seeing logic states 0 and 1. You can use the logic probe to check these logic states.

The dog ate my logic probe - great line, Ron!

Norman.

[prime]

Thanks soon as i get it i will start with sequence 9. Sorry for going on and on for me this is a challenge. pete

[Ron Rich]

Hi Norman,
To be honest-- she did not "eat" it--but she did bite it enough that the case was shot ! Ron Rich

[prime]

Hi guys moving forward and new observations, while doing the logic board test ( turn off unit, move switch on logic board to off, down, press clear, turn unit on) magazine started to spin, picked up a record, started to play ,i pressed cancel and record returned to magazine, i heard a few clicks and same record returned to platter. turned switch back to on position and still if i cancel record gripper returns to magazine, a few clicks no movement on magazine and gripper returns record to platter. I dont see this situation in manual. any thoughts Pete

[jukenorman]

Hi Pete,
I am sure that tells us something - the question is what? I think that part of the logic board test just mimics what happens when you turn the phono on as normal, ie the magazine motor is enabled and it completes one revolution until it reaches the home position (limit switch).

I'm going to guess that initially the magazine motor is operated as it should but because of a fault, sequence 13 (selection located) is being initiated (maybe IC407 is faulty for example). But in order to check out my guesswork, you are going to need the logic probe and the large schematic!

Norman.

[prime]

Hi guys tested logic board and hit tracker, all diodes, transistors are fine, i also checked all wiring going to the display unit. Finding all wires having good connection, i have come to the conclusion the display unit itself is defective. I can get a used replacement on ebay but i have also seen an led retrofit including computer chip. Which do you recommend ? I feel i need the display working to use the test procedures to itemize my issue. I feel it may be a chip thats gone. pete

[prime]

I was just wondering if there is a way to test the display to see if the gas has escaped

[jukenorman]

Hi Pete,
The main display is driven by a display driver in the profit setter. The hit tracker has its own integrated display - are you saying neither the hit tracker display or the main display are operating? The display driver chip in the hit tracker is the same type as in the profit setter. I'm sorry, I don't have much experience testing these displays.

Norman.

[prime]

That info is very help full, i will change the chip at least that will confirm if the display works or not. thanks

[prime]

I replaced the display chip with the one from the popularity board, now instead of just the credit display being blank, both sides were blank, i replaced with the original same thing. Before i replaced the chip the credit was blank but the select screen would show numbers if i pressed clear on the profit setter and selected numbers. While sitting looking at all connections the credit light came on, then the selection light and reset, also on the right screen two numbers appeared. Does this info help, i have already ordered new retrofit LED boards with matching chip just to eliminate a display issue.

[Ron Rich]

Hi Pete,
Is this "chip" a C-MOS, or LSI type IC ? Did you use proper anti-static proceedures when changing it ? Ron Rich

[prime]

Hi Ron this is the display chip, I have since found all has gone back to where i started from, credit display blanc, song playing and selection display works if i press clear on profit setter and select numbers, numbers appear but then disappear without engaging magazine. I have noticed if i play with the clear and press song numbers a few times ,a number in the playing window will appear and the magazine will activate and gripper will put 45 on table but not necessarily the number showing. Im starting to lean to logic board main chip, im not sure where to get a replacement.

[jukenorman]

Hi Pete,
I'm having difficulty following what is happening here in that events don't seem to follow any pattern eg displays coming on and then going off for no rhyme or reason that I can see! Are you sure the power rails are OK? I know we will have touched on the 9.6V but what about the others - have you looked at these?

Norman.