NSM Prestige ES 160 Fuse Keeps Blowing

[stepodj]

I just received my first jukebox, an NSM Prestige ES 160.

The symptoms I'm seeing are:

- No lights or power to the selector buttons/screen
- Upon inspection, it appears that unit is blowing fuses Si2 (1.25A) and Si3 and hence not powering (this appears to be the +5v and -5V aspects of the unit power the control computer)
- The LEDs (LED 201 and LED 202) to show power to the board are off as expected because of the fuses

I've tried swapping both fuses (only had 1A slow burn instead of 1.25A as I wait to order) and the fuses blew again. Not sure if 1A vs the 1.25A is the issue here, but having trouble finding 1.25A.

When I was purchasing the unit, the owner was trying to get the unit working and he did temporarily get the selector buttons/screen working and selecting a record after he swapped fuses. I think it then blew when I hit the reject button, but not sure that was the cause for sure as he was fiddling. He was just throwing any fuse in there available with the parts kit in the jukebox and potentially used a 2A fuse to get it working temporarily. But not sure if this did damage as that fuse seemed to blow too.

Any suggestions on how to trouble shoot the issue or electronics? I've got the full service manual and schematics (see attached)

A couple of pictures with circle around issues I've figured out so far.

Thx so much, very excited to learn.

Pic 1

Pic 2

[jukenorman]

The fuses are blowing for a reason! The power supply unit clearly has issues - check bridge rectifier, replace elecrolytic capacitors, check voltage regulators. These early ES NSM power supplies will present a reasonable degree of difficulty to the beginner because they require a considerable degree of dismantling to work on - lots of screws, spacers etc to remove, rectifiers and regulators mounted on heat sinks ie more screws, brackets and insulators. You will probably be muttering to yourself "who on earth designed this!".

While you have it apart, it might be a good idea to replace the electolytics on all the voltage rails.

Norman.

[stepodj]

Thanks. I've pulled out the board and starting to trouble shoot. Seems like there are only 4 electrolytic caps on the voltage rails so will go there first.

Anything else I should tackle while out? I heard it play music before the fuses blew so I belive the amps and preamps are working.

[jukenorman]

The electrolytics are usually the main problem. On the circuit that's blowing fuses, also check the bridge rectifier. If the electrolytic has gone short circuit, there's a chance that may have caused rectifier failure - I've seen it happen.

Norman.

[Ron Rich]

If, you would "comply with the requests" in the Hi Newbies post in our FAQ's section, and the same "requests" in our User Introduction section, it may make it easier for us to recommend a source for your 1,25 A fuse. Also-- what physical size fuse do you need ? Ron Rich

[stepodj]

It uses a 1 2/10 Amp slo blo 125v
. I belive it is the standard length which I belive is 30mm.. I. E not the short ones.

[stepodj]

Just a quick update...I replaced all the electrolytic caps in the power supply (C200, C201, C202, C203 I belive) as well as the diode for the bridge rectifier. EVerything is now working! Going to lubricate it up and start finishing the clean up and restoration.

[bulldurhames160]

Mines doing the same thing! What diode bridge rectifier are you referring to? Do you know part # or have a picture you can show? I’m in the process of changing all 4 caps but don’t know what diode you changed. Any help would be greatly appreciated! Thanks

[jukenorman]

The OP hasn't been seen on the forum for nearly two years so it's unlikely that he will reply. Do you have a manual / circuit diagram - if so you can investigate the circuit for the DC rail of the fuses which are blowing and check the diodes or bridge rectifier and replace like for like if necessary. However if exactly the same fuses as the OP are blowing, the diodes he would have replaced would have been 201 to 204 (BY251).

Norman.

[bulldurhames160]

Thanks for your help I appreciate it! This helps!