This post is a long shot, but here goes!
Given that there was only little over 6,000 MQ-101 units made originally, it's over 45 years since they were last produced, probably only a small portion of the units that remain in use, and a very few being operated in European mains voltage areas, there will not be many, if anyone who could answer this one;
I'm in the process of re-capping the power supply board of the unit as I have a mains hum on both channels.
I've been using a step-down unit to power the unit (around 120Vac) for the last number of months, and not sure or not if that is also contributing to the mains hum on the audio paths.
I've searched the web for the specs of the transformer, 159-092 or 3522104, and unsurprisingly, nothing.
Here are my observations & measurements-
Colour Coding - where
- Black, Black/Yellow and Black/Red represent the primary windings
- Red, Red/Yellow and Red represent the high voltage secondary windings
- Brown and Brown represent the low voltage secondary winding
Based on measuring the primary winding resistances
it leads me to believe the primary is connected to mains in the following configuration
Where the 117Vac is applied across the Black - Black Yellow wires. This means only half the primary winding is being used.
Logic dictates (at least to me) that if I was to apply European voltage( 230-240V) to the entire primary winding (Black - Black Red) rather than half, it should yield the same secondary voltages i need
Questions are;
Has anyone converted one of these MQ-101s to work on european mains voltage successfully?
Is my logic above correct?
I think the best approach would be to is to configure the primary to work with 230-240Vac, apply the 120Vac and confirm that the voltages across the secondary winding are half of the ones already measured.
Any advice would be greatly appreciated.
Given that there was only little over 6,000 MQ-101 units made originally, it's over 45 years since they were last produced, probably only a small portion of the units that remain in use, and a very few being operated in European mains voltage areas, there will not be many, if anyone who could answer this one;
I'm in the process of re-capping the power supply board of the unit as I have a mains hum on both channels.
I've been using a step-down unit to power the unit (around 120Vac) for the last number of months, and not sure or not if that is also contributing to the mains hum on the audio paths.
I've searched the web for the specs of the transformer, 159-092 or 3522104, and unsurprisingly, nothing.
Here are my observations & measurements-
Colour Coding - where
- Black, Black/Yellow and Black/Red represent the primary windings
- Red, Red/Yellow and Red represent the high voltage secondary windings
- Brown and Brown represent the low voltage secondary winding
Based on measuring the primary winding resistances
it leads me to believe the primary is connected to mains in the following configuration
Where the 117Vac is applied across the Black - Black Yellow wires. This means only half the primary winding is being used.
Logic dictates (at least to me) that if I was to apply European voltage( 230-240V) to the entire primary winding (Black - Black Red) rather than half, it should yield the same secondary voltages i need
Questions are;
Has anyone converted one of these MQ-101s to work on european mains voltage successfully?
Is my logic above correct?
I think the best approach would be to is to configure the primary to work with 230-240Vac, apply the 120Vac and confirm that the voltages across the secondary winding are half of the ones already measured.
Any advice would be greatly appreciated.
