Post by okeefem on May 12, 2021 14:07:39 GMT
Hi,
Apologies to all if this goes wrong as it is my first post.
A friend has asked me to repair his Wurlitzer Niagara 5. It has been inoperable for several years but did work about 10 years ago. - I have the manual.
After cleaning, replacing some mechanical parts, and repairing the power supply, I was able to get the basic mechanism working.
i.e. Adding credit, making a selection; the jukebox would pick a record and attempt to play it - there were some differences between the numbers displayed and those on the carousel. In other words, when the carousel was allowed to turn the displayed numbers were of a different number set to those on the carousel.
As I had taken all parts of the jukebox out of the cabinet to gain access to everything, I was adding credit manually with a simple wire; to ground the appropriate connection.
Although the jukebox would select a record and place it on the turn table (which turned) the record would not play because the arm would not lower and was not aligned.
To align the arm I was repeatedly adding credit and adjusting the arm.
During this process, the circuit board went into a kind of oscillation with one (unidentified) relay repeatedly being activated.
Panicking, I turned off the power.
The jukebox (computer) now exhibits the following:
Upon power on, the display shows 222, credits may be added, a selection may be made but the carousel is not activated.
Within 20-30 seconds the display starts to flash on and off. The period of "display off" slowly increases to a situation when (within another 20s) there is no display and no credit can be added (and obviously with no display likewise a selection cannot be made).
Currents appear to be on the low side compared with those in service manual.
The 30V (DC) rail starts to drop as the display starts to flash - I generally turn the power off by the time it hits ~23V
The 10V (DC) rail also drops but not as significantly.
The 5V (DC Regulated) rail remains constant in the time-frame of test.
Currents on 30V and 10V lines also "droop" (?).
I have replace the electrolytic capacitors on the 30V and 10V lines. I've replaced the diode on the 30V line.
Disconnection of the display does not stop the drop in the voltages (IMO Conclusion: the display itself is not the cause).
Disconnection of the optocoupler circuits by removal of the indicator diode does not solve the problem (IMO Conclusion: the optocoupler ICs are ok)
The combination of drooping voltage and current confuses me, so any assistance that could be offered would be greatly appreciated.
Thank you in advance,
Okeefem
Apologies to all if this goes wrong as it is my first post.
A friend has asked me to repair his Wurlitzer Niagara 5. It has been inoperable for several years but did work about 10 years ago. - I have the manual.
After cleaning, replacing some mechanical parts, and repairing the power supply, I was able to get the basic mechanism working.
i.e. Adding credit, making a selection; the jukebox would pick a record and attempt to play it - there were some differences between the numbers displayed and those on the carousel. In other words, when the carousel was allowed to turn the displayed numbers were of a different number set to those on the carousel.
As I had taken all parts of the jukebox out of the cabinet to gain access to everything, I was adding credit manually with a simple wire; to ground the appropriate connection.
Although the jukebox would select a record and place it on the turn table (which turned) the record would not play because the arm would not lower and was not aligned.
To align the arm I was repeatedly adding credit and adjusting the arm.
During this process, the circuit board went into a kind of oscillation with one (unidentified) relay repeatedly being activated.
Panicking, I turned off the power.
The jukebox (computer) now exhibits the following:
Upon power on, the display shows 222, credits may be added, a selection may be made but the carousel is not activated.
Within 20-30 seconds the display starts to flash on and off. The period of "display off" slowly increases to a situation when (within another 20s) there is no display and no credit can be added (and obviously with no display likewise a selection cannot be made).
Currents appear to be on the low side compared with those in service manual.
The 30V (DC) rail starts to drop as the display starts to flash - I generally turn the power off by the time it hits ~23V
The 10V (DC) rail also drops but not as significantly.
The 5V (DC Regulated) rail remains constant in the time-frame of test.
Currents on 30V and 10V lines also "droop" (?).
I have replace the electrolytic capacitors on the 30V and 10V lines. I've replaced the diode on the 30V line.
Disconnection of the display does not stop the drop in the voltages (IMO Conclusion: the display itself is not the cause).
Disconnection of the optocoupler circuits by removal of the indicator diode does not solve the problem (IMO Conclusion: the optocoupler ICs are ok)
The combination of drooping voltage and current confuses me, so any assistance that could be offered would be greatly appreciated.
Thank you in advance,
Okeefem
