Repair to VG88 Power Supply

Started by mgriff66, April 09, 2018, 03:27:28 PM

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Hi all,
this is a request for information with regard to the replacement of a VG88 internal Kitamura Kiden R-Core transformer that supplies the PSU in a VG88 unit. I have searched long & hard for information on the net but have been unsuccessful. I am in the UK ( 240vAC) & have contacted Roland UK who promptly replied & provided the service manual which i had stated that i already had, the manual not providing any real reference to the transformer & no output winding voltages.
My unit has a broken primary winding (yellow wire for anyone familiar) which is non repairable as it has snapped off where it exits the winding former. A replacement appears to be the only option but i can not find information pertaining to the AC output voltages that feed the power supply PCB.There is a dual rail supply, so ?v-0-?v  and another pair of wire that provide one more voltage.
I would be very grateful if any member could enlighten me as to these values. Ebay has R-Core transformers available with multitudes of output voltages, i just don't know which one i require.
Any help would be most gratefully received.


I could measure the volts on a VG-88, do you still need this information?


thanks for your offer. That would be greatly appreciated.
I had given up waiting for a reply so had not been checking the forum.
Best regards,


I will try to check this tonight, as I've been out of town... I'll post the values soon.


Ok, so ... my unit is the 120v model (I think this is important because of the wire colour chart that is printed on the board).
Which wires do you want to check?


thanks for your help'
Your transformer has the same colour wires as my 240v version. I require the secondary winding output voltages, orange/orange & the red/black/red centre tapped trio so red to red will be sufficient thanks.



In the UK - Seek a transformer which has a 240VAC primary , and dual secondary = 20VAC Center tap & 10VAC

Roland P/N 22453553D0 (TRANSFORMER 230V/240V) = AC Mains Internal Transformer for a UK VG-8


Roland P/N 00128789 ( CCT 2102-0201 2.5A/250V/2P  / AC Inlet(230V,240VE,240VA))  = AC Mains AC Power Inlet for a UK VG-8

Good reading on the Kitamura Kiden


These values are from a 120V version VG-88.
The 120V version is determined by the position of the blue and yellow wires soldered to the board (Ter4 and Ter3), as stated in the reference table/chart printed on the board.

Measurements carried out with white connector (CN9), coming from the transformer, removed from the board, and in the shortest possible time (to avoid significant mains supply voltage flutuation).

Ter7 to Ter6 (AC Cord) = 115.1 V  (AC)

Orange to Orange = 10.6 V (AC)
Red (Closest to board printed white "CN9" label) to Black = 21.4 V (AC)
Red (next to Orange) to Black = 21.5 V (AC)
Red to Red = 42.9 V (AC)

Continuity Test (to check coils):
Red, Black and Red are connected with each other
Orange and Orange are connected with each other

As you can see, my mains supply is not 120V (it is 115V), so be carefull with the reference voltages for the secondary windings (the above measured values should be 4.25% higher, if 120V is to be considered at the primary winding).

I wasn't expecting such high values...  Why does it need such high voltages?--- It has no valves/tubes in it, nor an amplifier power section!... ???

I hope this helps!  ;D


Thanks both for the info.
I can see now that the VG8 & VG88 are obviously different as the center tapped winding on the VG8 according to the drawing is 18vac ct where as the VG88 as kindly measured is practically 43vac center tapped. The orange pair secondary is close at 10.6 & 9v.

The above may suit if regulation cct can handle the few extra volts. I will have to check.
Thanks again guys, will keep you updated and post images of finished repair as a reference for anyone else requiring this repair or modding from a US to UK or vise versa.


Bonjour, je souhaiterai changer le transformateurKRT-8D-A-008S2 100 Volt par un transformateur 240 volt pour un alimentation VG-88.
Est-ce possible ?
quel est la référence du transformateur 240 V ?
où puis-je le commander ?
MatérielAC  concerné : V-Bass n° série ZT42386
AC 100V~50/60 Hz
Merci pour vos réponses