Vintage Synth Repair

I have been having this VCF problem for a while now and I decided to 
get the Arp 2600 service manual and fix it my self.  I have a grey 
face Tonus Arp 2600, however, it has a 4072 VCF.  The first thing I 
noticed are components which are not in the parts list or on the 
schematics or board layout drawings in the service manual.  

This picture:  http://68.55.220.59/104.jpg shows the 4 blue 
components which are bridging gaps cut into the track work.  Neither 
these components nor the cuts in the trackwork are mentioned in the 
service manual.  Can anybody tell me what these blue components are 
and why there are cuts in the trackwork?  Each track corresponds to 4 
of the 5 audio input sliders on the front.

In the parts list of the service manual it lists C1, C2, and C3 as 
all being 1uf CAP TANTALUM 35V 10%, however, from this photo This 
picture:  http://68.55.220.59/106.jpg, you can clearly see C3 is a 
ceramic disc cap.  

Has anybody worked on a 2600 that looked like this on the inside?  
Can anybody shed some light on where to start looking for problems?  
Should restore the components to the exact components in the parts 
lists?  should I remove those 4 blue components and restore the track 
work?

The rest of the unit works fine.

Thanks in advance,

Ethan

I have been having this VCF problem for a while now and I decided to 
get the Arp 2600 service manual and fix it my self.  I have a grey 
face Tonus Arp 2600, however, it has a 4072 VCF.  The first thing I 
noticed are components which are not in the parts list or on the 
schematics or board layout drawings in the service manual.  

This picture:  http://68.55.220.59/104.jpg shows the 4 blue 
components which are bridging gaps cut into the track work.  Neither 
these components nor the cuts in the trackwork are mentioned in the 
service manual.  Can anybody tell me what these blue components are 
and why there are cuts in the trackwork?  Each track corresponds to 4 
of the 5 audio input sliders on the front.

In the parts list of the service manual it lists C1, C2, and C3 as 
all being 1uf CAP TANTALUM 35V 10%, however, from this photo This 
picture:  http://68.55.220.59/106.jpg, you can clearly see C3 is a 
ceramic disc cap.  

Has anybody worked on a 2600 that looked like this on the inside?  
Can anybody shed some light on where to start looking for problems?  
Should restore the components to the exact components in the parts 
lists?  should I remove those 4 blue components and restore the track 
work?

The rest of the unit works fine.

Thanks in advance,

Ethan