77 X5 Fuse Si5 blows as soon as I plug in the jukebox

[TheFonz]

So I recently started working on this JB to get it back up and running again. It's been sitting for a while and appears to be all in tact.  So I replaced all the fuses as a start as i noticed some were blown.  The issue Im having is that one of the fuses is blowing as soon as I plug in the JB.  Its the Si5 Fuse.

Im having trouble attaching a pic.  But from left to right here is how the 5x20mm fuses are layed out.->  |Si5|Si4|Si6|Si3|Si2|   And are all labeled to be 2A each(slow blow) 

So Im trying to troubleshoot why this fuse is blowing but here are the issues I'm having with the documents and drawings.

1. I can not find Si5 fuse anywhere in the wiring diagrams and schematics that I have. All other fuses are shown.  However it does mention it in some text on a DWG that Si5 and Si6 feed power to the changer i believe. Although it shows Si6 on that same dwg, it does not show Si5. Can someone please confirm what Si5 feeds and if anyone has a diagram where it shows this Fuse?   I can and will pull the Amp off to follow the wiring from the fuse to see where it goes, but be better if a dwg would be handy.

2. I have all 2A slow blow fuses in there now, as that is what the label next to the fuse holder indicates they all to be. However The manual indicates that some of these fuses should be 3.15A, so I'm confused a little there. It's possible this is not the original AMP for this JB and was replaced at one point, who knows.  The other thing i noticed for the manual for this unit is that it shows the fuses in a pic but only show 4 fuses, another reason Im thinking replaced amp. 


Anyways, Any info or clarifications would be Great, my first post obviously.  Thanks in advance.


Glen 

[Hildegard]

Hi Glen,

I assume you have the service manaul for 1977.
In the parts list Fig. 17 shows the installed amplifier - should be a S77. Sometimes the amps have a small label somewhere showing this number.
Fuse Si5 is shown there. (S77 means Stereo Amplifier of 1977; a mono amplifier of that year would be M77.)

The amplifier diagram #43 700 100 S 5 for amplifier S77, dated 10/76, shows fuse Si5. It is r.h. of the the main transformer below the fuses Si2 and Si3.
The schematic informs also that fuse Si5 is only be found on stereo amps, not on mono ones.
This is what the fuses are for.
Si1: in stereo amps only, 3.15A for 115V, otherwise 2A
Si2, Si3: amplifier supply, 3.15A for stereo and 2A for mono
Si4, Si5, Si6: changer supply, 3.15A always
All fuses are slow blow.

I guess there is a 30V~ problem in your X5.

Hildegard

[TheFonz]

Thanks Hildegard!   Appreciate the detailed response.   I will take this info and check my documentation and do some trouble shooting.  First thing I will check is what Amp i have.

[TheFonz]

Update  I can't seem to get the INSERT IMAGE function to work, If someone can show me please do.

I have the same drawing you mentioned, same date. for the S77 Amp.  There is a SI6 shown on my copy below the SI2 and SI3 on the r.h. side of the XFMR.   Perhaps the 6 is actually a 5 ??, as my copy is not perfect.   Tks    I still don't see Si5 in the transformer diagram.   Mine says...43 700 100 S 5 for amplifier S77, dated 10/76.  Not sure if you can send me a clip of your diagram or even email me a copy of yours. 


I checked the amp.....My amp is a S72, not sure how it differs from the S77.   

Tks

[Hildegard]

I checked the manual again. You might be right - what I've read as a 5 could be a 6 too .... All in all I can only find 5 fuses, not six. Very funny.

Do you have the whole manual?
Check page 8 "The power Supply". The German description says that the transformer supplies the mechanism via Si4/Si5 and two diodes with ca. 26V and via Si6 with 30 V. Maybe one of the diodes is faulty?
But both the English and the French translation on same page don't mention Si5. Also very funny.
Another information on the amp parts list and the functional diagram for X5: USA models might have UL standard fuses. Then it is
Si1: 6A
Si2 - Si5: 2A
Si6: 3.15A
The functional diagram itself shows only Si1, Si4 and Si6.

Yes, you have the same amplifier drawing than I do. Sure I can email but not sure if that would give more clue.

Sorry, I don't know about the Insert Image function at all.

[TheFonz]

Mar 28, 2024 22:30:01 GMT Hildegard said:

I checked the manual again. You might be right - what I've read as a 5 could be a 6 too .... All in all I can only find 5 fuses, not six. Very funny.

Do you have the whole manual?
Check page 8 "The power Supply". The German description says that the transformer supplies the mechanism via Si4/Si5 and two diodes with ca. 26V and via Si6 with 30 V. Maybe one of the diodes is faulty?
But both the English and the French translation on same page don't mention Si5. Also very funny.
Another information on the amp parts list and the functional diagram for X5: USA models might have UL standard fuses. Then it is
Si1: 6A
Si2 - Si5: 2A
Si6: 3.15A
The functional diagram itself shows only Si1, Si4 and Si6.

Yes, you have the same amplifier drawing than I do. Sure I can email but not sure if that would give more clue.

Sorry, I don't know about the Insert Image function at all.

Thanks

I will check the manual as you described.    Like i said, my amp must of been replaced with an S72 and all the fuses  are all labeled and shows the fuse sizes to all be 2amp.   Right now I have a 3.15A in Si5 after trying the 2A still blows.  Anyways Im going to trace the circuit and see what's causing the fuse to blow. 

Maybe if i look at the wiring diagram for a 72 juke box, not sure what model it would be, might shine some light on this.  Perhaps Si5 is feeding the transformer on the 72 model and should be higher.   

Appreciate the help
glen 

[Hildegard]

Ok, that answers the question about the fuses.

Amplifier S72 uses 6x 2A slo blo fuses. Si5 is for the 30V circuit if I understand the schematic right.

It seems there is no difference in fuses between 117V and 220V. At least neither the parts list nor the schematics say so.

www.jukebox-world.de/Forum/Archiv/Schematics/S72.pdf

Hildegard