Rowe CD100c display module problems (part II)

Hello all, posted this issue a few weeks ago and it was thought that it probably was the display module itself, unfortunately not so. Here is the background info:

The jukebox was not being used for a few months during construction and today I went to turn it on and ran into some issues with the display module. It is not working!!!

The entire jukebox seems to be functioning fine, Songs play, I can select songs, put coins in etc, but no display. The display is maked "DIGITAL DISPLAY ASSY 40855001and the LED on the back of the computer board of the display is not lit. I have a little under 9 DC volts at the black and brown wires the feed the display.

So has the display module gone bad? I am little concerned since the LED on it is out that perhaps it is not getting power. I am not sure if I am reading the voltage across the right wires. Is there another way to test the display? The manual isn't much help. Any other thoughts or suggestions? Anyone has a good (cheap) source for another display module if that is truly bad? I do not mind replacing it but I would love to know that it is truly the problem before I switch it out!!!!


So I was able to get a replacement display module and try it and unfortunately the same result, no display. Since then I was then able to try both displays on my brother's jukebox (same model) and both displays work perfectly, so I am assuming the issue is not the display itself. So what is next for me to take a look at? Power supply to it?
It seems, although I am not 100% sure, that there is 9 volts at the wire harness socket without the display unit plugged in but when I plug it in it drops to 2 volts, it this typical? The rest of the Juke seem to be functioning fine. So what would the next line of checking?

Desperately trying to get the jukebox back up and running so any and all info wold be greatly appreciated. As always thanks ke

Hi ke,

It sound as if you have a problem on your jukebox power supply if the voltage drops down to 2 volts on load.
I suggest that you check out the circuit board on the power supply for dry joints (cold joints USA) on the connection pins from the transformer to the circuit board.
You can test the power supply out of the jukebox by using by the use of 12 volt lamps as the load whilst checking the voltage.
use a 12 volt (say 1.2 watt max) across the 9 volt DC supply and use two 12 volt lamps in series across the 28 volt AC and 28 Volt DC supplies.

Regards
Alan Hood
ami-man
UK

Mr. Hood, thanks for the response. Sorry I am not that familiar with all this so I would appreciate some further clarification and explanation.

Could you clarify what you mean by "Cold joints", are you referring to a failing solder joint?
Does the manual (I do not have access to it at the moment) have a good schematic of the power supply and a way to diagnose it?
Is the test you describe something I can do on the jukebox itself and am I looking to see if the voltage stays consistent before and after the load? If there is a voltage drop what could be causing it other than a cold joint???
Anything else to look thru?

Thanks in advance Ike

Ike,
All products that use either A-MP or Molex brand "header plugs", are subject to "cold" (or "dry") solder joints, where the printed circuit board joins the metal "pins" in the plug. These must be re-heated and new, fresh solder applied. Also, more apt on A-MP rather then Molex pins, the formed pin itself, inside of the housing becomes "de-formed". In this case each pin must be removed from the housing, cleaned and reformed --one at a time--MOST Rowe plugs are A-MP brand. Ron Rich

Thank you Mr.Rich for the explanation. Does not sound good, I guess age catches up to all of us!
Things have now gone even more serious. Up until know the juke box worked fine other than the display. However after shutting of the power I removed the 9 pin connector that is on the power supply circuit board and replaced it to make sure I had good connection. Well when I powered up the jukebox I have no sound. The speakers crackle when I turn on the power but nothing, everything else seems to be working fine.

Any thoughts on this new issue? At least I could play some music, now I only get a hummmm.

Is there any way to verify that the power supply circuit board is working properly all three LEDS are lit up?

Thanks again
Ike

Ike,
There is "no relationship" between the power supply board and the amp.I would need to assume that you have knocked off a plug going to/from the amp ?
On the PS--the plugs used on that unit are famous for not "making good contact"--you MUST do as I wrote before-- The only way to tell if it's working right is to measure the voltages--note the "8volts" must be 9+volts if using a CDM 12, or newer player. Ron Rich

Mr. Rich than you for the response. Would you please clarify "The only way to tell if it's working right is to measure the voltages--note the "8volts" must be 9+volts if using a CDM 12, or newer player." Are you referring to Mr.Hood's post about checking to see if there is a drop during a load? If not what would I be checking and how, I did not see anything in your post with regards to that.

With regards to sound I was very cautious when removing and reinstalling the connector and I double checked no obvious loose wire. The amp seems to be working but the CD player is playing but seems not to be producing any sound. Any thoughts?

As always in your debt Ike

Hi Ike,
The easiest place for me to check is at the CCC--just remove it's "cover", make sure it can't short out on anything, plug all plugs back in, and check at the power supply plugs--
A "quick check" for the amp is--IF, you have the older amp that has the "phono cartridge input" jack--wet you fingers and touch the jack--you should get "hummmmmmmmm if working right ( remove the mute plug first).
Ron Rich

Hello Mr.Rich thanks for hanging in with me, some of this is new to me. so I am not sure that I am following your instructions 100%. Here is what I have so far:

With regards to the lack of sound, I tested the amp as you said "very cool test." I definite have a hum. Also, if I plug in my I-pod directly into the CD input jacks of the amp, and then take the and move the power switch to OFF on service switch, It hen have music playing thru the jukebox. if I move the power switch to ON the music stops. I have also tried to hook up some mini speakers I have to the CD player audio on the CD player but there doesn't seem to be any music coming out of the it. Everything on the CD player seems to be working. Not sure what any of this means but I think the amp is working but the CD player is not making any sounds????!!????

With regards to power supply and drain I checked for voltage at P4 and P5 and I have 28 volts and 9 volts at the appropriate pins, which I believe is correct. I also checked at the harness for the display module and there is a little bit of a fluctuation but at about 8.2 volts without the display plugged in. However, when I plug in the display, the voltage drops down to 2.7 and the display is not lighting up. Not correct??? Should the voltage stay constant ???

I hope this is what you where asking me to check??
Well this is what i have so far. Very sad because we just started using the Jukebox after a 18 month mothball during construction. .

Any thoughts??? Thanks Ike

Ike,
Sounds like connector problems, I described earlier--You have 9 volts at on end, but only 8.2 at the other--
You said you had access to another phono--why don't you remove the display, and try it on the other phono--also, the CCC.
As for your player/sound problem--which model player is installed in that phono ?

Mr.Rich Is the issue you are referring to the actual pins solder to the circuit boards? If that is the case why would the voltage be correct leaving the CCC but drop at the display module harness? How would a "cold solder" cause the drop? Also why does the voltage drop when the display is plugged in? ( last time I had to worry about this was High school physics!!!) Does power demand/drain accentuate the cold solder issue? Is that wire connection uninterrupted all the way back to the CCC? Could it be a bad wire?

I have been able to try both displays on my brother's jukebox and both displays work perfectly, so I am assuming the issue is not the display itself. But the power or the communication to it. Unfortunately the other jukebox is not close by, I was there over the holidays. I would also hesitate to mess with someone else Jukebox, even my brother's to that degree. These appear to be quite finicky and would not want to feel guilty if something was to go wrong with his.

The ID on the CD player is, I am not sure, "CD Pro"??? Y There are some faded stickers that are illegable. If that is not it what do Look for to ID it??

Thanks Ike

Ike,
"Cold solders" tend to "open" under load. Yes, I am speaking of the point where the pins are soldered to the PCB.
CDM PRO is a late style player ( could be a "Pro 1" or "Pro 2"--directly interchangeable). All players are extremely sensitive to static electricity, and all anti-static precautions should be observed when anywhere near a player, or circuitry that goes to the player.
Ron Rich

Mr. Rich thanks for the clarification with regards to the cold solder issue, so it could be "bad" solder on the CCC board, I assume? So repair or replace it?

With regards to the CD player, all this rummaging around the jukebox may have caused some issues I assume. Is there any way to test it? There is no light on the BOARD ERR LED if that means anything. I am curious as to why does the amplifier not play the I pod when the power switch on the service switch is set to ON and only OFF? Also if I plug my mini speakers into the CD player's output jacks if there was sound should it be coming out? Could something be shutting down the actual music from th player but not the other functions?

Thanks Ike

Ike,
The "cold solder" (or "bad pin") could be ANYWHERE, on any "board"--
If you had read my earlier post where I said to "remove the mute plug", while "testing" the amp, you might just have realized that there is an amplifier mute function provided, externally, when no CD is playing.
Ron Rich

Well my bad, I assumed that the "jumper" on the phono cartridge pins was the mute plug. Took a while but finally figured out that the wire at P13 on the CCC is the mute plug. When pulled it the amp plays the I pod when the switch is on.

This is now beyond my ability, but I am curious what a tech would do in the field, since he/she is not repairing circuit boards, just start replacing boards until the problem solves itself?

Also I would love to know if I plug my mini speakers into the CD player's output jacks and there is no sound, does that mean the CD player is not producing any or could it be a issue elsewhere interrupting it?

Lastly does anyone know of a good tech in the Long Island area on New York City?????

Thanks again for all your patience!!! Ike