Dear Friends!
Unfortunately, after the event mentioned in this subject, the new fuse will be blown. One of the primary windings of the power transformer (Brown-White leads) has a DC resistance of 0.5 ohm.
I would like to ask if there is an EU voltage (230-240VAC) power transformer available for this type?
Thank you!
Regards from Csaba Hetenyi (Hungary)
Hi Mickey
That does seem quite low, but are you sure the power transformer is dead?
The 2/50/2 is in production, however, I do not know if the power transformer is a drop in replacement for your older VHT model.
I need some advice from the shop… please standby.
Thanks Dan for your reply!
In the meantime, I desoldered the primary windings of the mains transformer and also checked with DC resistance measurement. I will attach pictures of the measurement results. The primary windings are paralleled, but I also measured them separately. The mains voltage is applied to the Black - Brown leads, which have a DC resistance of around 2.5 ohms, which seems very low.
Thanks very much for your research!
Thank you Dan!
Looks like you were right and it’s not the power transformer (I used a FAST fuse instead of the SLOW one)
However, it seems to be a universal transformer as it has two primary windings. In Hungary the official voltage is 230-240V AC. If I connect the primary coils in series, am I doing the right thing to convert the device from the original 117V AC version to 230V AC?
Each primary coil has 3 leads. I see that BLACK lead is the neutral, BROWN is the 117V tap, WHITE is the full coil (130V according to my measurements). Which ones should I have in series for 230V? BLACK-BROWN and BLACK/WH-BROWN/WH coils?
The official voltage of the rear FAN is 120V AC, which was previously wired to the BLACK and WHITE coils, which would give a voltage of around 130V AC. This still seems feasible if it stays in the same place it was before (the “lower half” of the previously paralleled but now in series primary coils).
Thanks in advance!
Hi Mickey
I’m glad the Power Transformer came back to life. It’s basically never the transformer. I think Steve might have seen one or two transformer issues with all VHT and Fryette products, something like that.
It does seem to be reconfigurable. But I’m afraid we cannot support this as a user intervention; it’s just too dangerous for end users to be working on anything to do with mains power and high voltage. You are obviously technically inclined, but I recommend sending it to a reputable repair technician near you. See here we can help with that, Can I get my Fryette product repaired at a local repair shop? If you cannot find someone local and are willing to ship within EU, I can send you contact information for our recommended repair location.
Regards,
Dear Dan
Thanks for the confirmation!
Yes, I fully understand that this kind of conversion is usually not user-performed due to electrical safety and other considerations.
In the meantime, I have done the rewire on the PT primary coil.
I wonder if I can ask what the voltages on the secondary side should be based on the factory recommendation?
I have attached a drawing of the PT. I am currently supplying the mains voltage at the highest possible primary voltage (which is officially 230VAC for us) So in the drawing, the mains voltage goes to the lower and upper ends of the primary coil (outlets 3 and 4 are connected together). So the secondary side voltages are on the high voltage secondary coil (red-red):
STANDBY: 358VAC,
CLASS A/B: 345VAC,
CLASS A: 330VAC
HEATER: 5,6VAC
Yes the heater voltage is too low. It was exactly 6.3VAC until the primary side leads 1 and 5 were energized, but then the secondary voltage was so high that even in CLASS A/B mode the power tube was redplated (in my case 4x EL34).
What should the secondary side voltages be according to the factory recommendation?
Thank you very much, Regards.
