Fisher 500C Receiver $400 Walnut Cabinet, New Output Tubes

[Scott Novak]

Fisher 500C receiver, Serial Number 61119 T, WITH Walnut cabinet for sale. $400.00 The cabineit is in fairly nice, but not perfect condition. All of the brass knob caps are present. See photos.






The output tubes are a brand new quad matched set of JJ Electronic 7591 S. The bias currrent has been set for an average of around 35 mA.

There are two NOS 6CW4 Nuvistors.

There is one NOS 6HA5 tube.

All tubes, including the new tubes and NOS tubes, have been tested with a Hickok 539C tube tester and are in good condition with the exception of the 6HR6. Please note that the blue on the tubes is 3-M painter's tape with the tube measurements and tube numbers written on the tape. This tape should be removed before use,

While the tuner actually works well as is, I discovered that the 6HR6 tube was a bit gassy and there was a slight bit of heater leakage. Most tube testers will not even measure this leakage. However, I am obtaining a replacement 6HR6 and will also measure the replacement tube to make sure it is good in all respects before I ship the receiver.

There is one dial light that is burned out. They cost between $2.00 to $5.00. If I am able to find one in town I will replace it. Otherwise it will ship with one dial light not working. It is fairly easy to replace.




Three of the electrolytic filter capacitors have been replaced. The 4th multi-section electrolytic capacitor appears to be in good shape. I can measure a reduction in ripple voltage at every stage of the power supply filter capacitors.

When the stock selenium rectifier becomes weak, the bias voltage for the output tubes decreases and allows the output tubes to run with too much idle current which will cause them to wear out faster. If the bias voltage drops too low, the output tubes will turn cherry red and fail. A weak selenium rectifier also causes the filament voltage to the 12 Volt tubes to drop below the correct amount and the sound quality will suffer.

The troublesome selenium rectifier has been replaced with a silicon bridge rectifier to eliminate these problems.

The main rectifier diodes have also been replaced with more reliable higher voltage and and higher current rated silicon diodes.

HOWEVER, I would highly recommend buying and installing the SDS power supply capacitor upgrade board kit. ANY audio amplifier that is over 15 years old can benefit from the sonic improvement of today’s higher quality capacitors. Not only do today’s electrolytic capacitors sound better, but the improved electrolytes and seals last longer.

http://store.triodestore.com/sds500cbrdprts.html

If you are not capable of installing this upgrade kit yourself, I can install it for a very reasonable price. I am an electronic technician and graduated from Northwestern Electronics Institute in 1978.

But the receiver is very listenable just as it is. But with the upgrade kit the receiver can sound better than when it was new.

The powerline voltages in the USA were lower when this receiver was designed. When you connect a stock 500C to 120 VAC household current, the filament voltages are excessive and cause the tubes to fail prematurely.

To compensate for this problem I have added resistors in series with all three of the transformer filament windings to reduce the filament voltages to the correct amount, so the tubes will not wear out prematurely.

I was careful to position the resistors to still allow the installation of the SDS power supply filter capacitor board without interference, if you wish to upgrade at a later time.



The B+ voltage was also adjusted where necessary to insure proper operation of the receiver.

There are further upgrades that a person can do to the Fisher 500C to improve the sound quality. But the first improvement should always be to improve the power supply filter capacitors.



Local buyers may pickup & save shipping cost. I will accept cash if you are local.

Shipping weight is 48 lbs from 55112. I will ship it Parcel Post, UPS, or Fed-Ex as you prefer.

Mailing is ACTUAL COST, NO Handling charges!!! Add insurance if desired.

I accept PayPal and can also accept credit card payments through PayPal. I only accept PayPal from buyers with verified addresses. I only ship to the verified PayPal address.

I will not accept a return for cosmetic reasons. Look carefully at the photos before you decide to buy.

sanovak@comcast.net

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[Scott Novak]

Sale Pending Payment