I just got a Eico regulated power supply but without the schematic or any doc. The C- and the VAC all work fine, but the high voltage. Was cleaning in the basement a bit this afternoon, and stumbled across the schematic for this old Eico power supply on my work bench that’s. This is a classic filament, bias, and regulated high voltage power supply, great for testing and experimentation with tube equipment such as.
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Recently my longtime trusted Eico regulated high voltage DC power supply succumbed to a catastrophic failure — a shorted transformer winding.
The power transformer has a separate eic that supplies screen voltage to the 6L6 pass tubes. This is a half-wave circuit that was rectified by one original 1N silicon diode.
Unfortunately, this old diode shorted and took the 0130 winding with it, thereby ruining the transformer. I use my HV power supplies on a daily basis for a number of tasks such as component testing high voltage diodescapacitor reforming, insulation testing, mocking up tube circuits, and many eido purposes. The applied voltage is much too low to indicate whether the diode is shorted.
Many diodes will pass a DMM diode test but are, in fact, shorted when operated at the high voltages seen in the circuit. This transformer failure caused me to consider how unprotected most transformers are in vintage gear. In many cases, a shorted cheap component such as diode or filter capacitor can ruin a very expensive or sentimental piece of equipment. I installed an ICL to limit inrush current at power-on. I replaced the rectifier tubes with fresh silicon ultra-fast diodes because Eio wanted to reduce the heat inside the cabinet, promote stability, and reduce transformer load 2.
Classifieds Eico HV Regulated Power Supply
One of the cheapest circuit insurance you can buy is to place diodes in series. If one diode shorts, you still have another one to continue proper operation of the circuit. Likewise, series diodes sum their voltage ratings, so the circuit is more robust anyway. For the price of a quality ultrafast diode eicp a reputable supplier — approx cents each for a Fairchild UF 1A, v — this protection is a bargain.
EICO Variable DC Power Supply V Restored | eBay
The bias supply 6X4 is a half-wave circuit, so I used 130 in series. Likewise, I used two UF in series in the screen supply, which was the winding that failed in my old power supply.
In addition to stacking the diodes, I installed fuses for each secondary winding. First, I fused the center-tap of the HV winding eicl a ma fuse mama fuse should be reasonable in this circuit. I fused the screen winding with a 62ma slo-blo fuse, which was the smallest that I had available.
Eico 1030 HV Tube Power Supply Question
I fused both 6. In this power supply, though, I did leave a 40ma PTC in the screen supply, which helped to mitigate inrush current and possibly added some transformer protection. The first section of the DPDT switch replaced the original in the same manner. I added a protection diode in series with the current meter to prevent current from reversing thru the current meter. Transformers can blow in the blink of an eye Recently my longtime trusted Eico regulated high voltage DC power supply succumbed to a catastrophic failure — a shorted transformer winding.
Regulated Power Supply 1030
Phase Linear …on the bench! This website discusses repair of electronic items.
Electrical voltages are present and represent a danger. Repairs should only be attempted by a qualified technician. We do not provide free personalized troubleshooting. All content is the opinion of the author and not intended as advice.