Erres KY585 radio (1959)

This is a nice late 1950-ies radio with AM and FM. It has a “piano key” bandwidth switch, luxurious tone control options, light bar tuning indicator and good sound. The valve line-up is:

• ECC85 as FM frequency changer,
• ECH81 as frequency changer on AM or first IF amplifier on FM,
• EF89 as first AM IF amplifier or second FM IF amplifier,
• EABC80 as AM detector, FM ratio detector and AF pre-amplifier,
• EL84 as AF output amplifier,
• EM84 tuning indicator,
• EZ81 as mains rectifier.

I acquired this radio in January 2025 through an Internet second-hand site. Actually, I wasn't planning to buy this radio. It came as part of a combination deal. Its condition was awful: smelling of mold, having badly looking corroded brass ornaments, holes in the speaker cloth and chipped paint. There was mold in the cardboard back panel, in the speaker cloth and in the general dust inside.

Then all of a sudden, I felt challenged to make it work again. Someone tried to fix it before but had given up, as the speaker and output transformer were disconnected. The many small damaged spots at the front were intriguing: splinters were struck from the Bakelite cabinet and from the paint at the front. There was even a small splinter missing from the glass tuning dial. The holes in the speaker cloth looked as if someone had been poking a sharp stick at the speaker.

I first treated the cardboard back panel and bottom cover with a bathroom mold cleaning product. That seemed to have some effect: the grey haze covering the letters disappeared mostly. The cardboard back and bottom panels were also warped badly by a long exposure to moist. To flatten them again, I wetted them and squeezed them between a set of boards for three weeks. After drying, I would seal the surface using a spray varnish.

The loudspeaker was affected by mold and had a number of holes in the membrane. Someone had tried to repair it using pieces of curtain, rubber glue and sellotape. It was looking ridiculous. The speaker wires and other wires to the output transformer had been cut. The power transformer was rusty. After some inquiries on the Dutch forum on old radios, I was offered a replacement loudspeaker and some components of an Erres KY595, a similar radio. I also received an original speaker cloth, old but in one piece.

Unfortunately, replacing the speaker cloth didn't go well. The replacement was stained so I tried to wash it thoroughly. Some stains were hard to remove so I scrubbed the cloth with ox bile soap. That was too much for the delicate old yarns. Threads were broken and again, the speaker cloth had holes in it. After drying, the cloth had shrunk and had to be stretched, which resulted in the holes getting larger. I tried to patch the holes but this only made it look worse. To summarise: the replacement cloth was ruined and had become unusable.

On a Dutch auction site, I found a newly woven speaker cloth that, though being different, did have horizontal golden stripes with about the right distance, which gave it a general look and feel that fitted the radio well. I decided to drop originality and just make the radio look good again. Pundits, puritans and know-it-alls may frown upon this but it was my best option. I fixed the cloth to a wooden frame and tensioned it. At the first attempt, I used bone glue because Erres had used that on the original. It turned out to dry too fast to properly apply the new cloth. Finally, I used white glue. That is easier to apply but impossible to remove afterwards. So be it.

Then I started with the electronics.

I carefully removed the tuning scale glass and unsoldered the wires to the tone controls that are attached to the glass. I put the glass with the tone controls aside. This way I could get access to the tuning cords while avoiding damage to the glass in the course of the repairs. The paper diffusion screen behind the dial glass was filthy, with a layer of dust and specks of mold. I made a temporary connection to bridge the tone control circuits and bring the audio signal to the output amplifier.

I removed all valves and connected the power transformer to mains, idling. It didn't run warm and the voltages were all ok, so the transformer didn't seem to have any real damage. It was visible that the isolation between windings wasn't paper but plastic film, so not very sensitive to moist. I removed most of the rust with a steel brush and then sanding paper. After this, I greased it with WD40 to stop the rust. Then I cleaned the chassis and removed rust spots from the frame of the tuning capacitor using a glass fiber brush.

Reforming the main power supply electrolytic capacitor seemed to go well. But the electrolytic near the output transformer was leaky so it was replaced. I checked the output transformer and was able to reconstruct all the connections to it. Then I replaced the paper capacitors. Most of them were really leaky and some of them were in a position to cause damage, such as the capacitor across the output transformer. Fortunately, the KY585 already has a number of polyester and ceramic capacitors that did not need to be replaced.

After putting back the valves, I connected the radio to mains and turned it on. It gave an impressive hum. The voltage on the reservoir capacitor had a tremendous AC ripple indicatig the capacitor was faulty. I had checked its leakage current during reforming, but not its capacity afterward. I found a suitable replacement, a bit taller than the original, made in Germany. The original had the Hunts brand, but the only Hunts replacement I had in store turned out to be leaky and unusable.

Now the radio was working! But on FM tuning was difficult. The maximum on the tuning indicator did not correspond to the best reception and the sound was distorted. I started to align the FM ratio detector and IF transformers, but I could not find a good setting for the ratio detector. Using my RF generator with sweep function, I got a distorted detector curve. On the Dutch forum on old radios people suggested to check the ceramic capacitors in the ratio detector transformer. These are silver plated ceramic tube capacitors, but they are not sealed, which leaves the silver vulnerable to corrosion. I extracted the detector transformer and measured the capacitors.

This measurement results were suspicious. But not conclusive yet. I opened the aluminium can and removed the capacitors to check them individually. It turned out they had partly lost their capacity. I found replacements that measured good and fitted them in the can.

After this, aligning the detector transformer was easy and resulted in a nice symmetric curve. The output signal was stronger now, the sound was much better and the best sound coincided with maximum reading on the tuning indicator, as it should. I aligned the other FM IF transformers and the FM tuner. After this, I also aligned the AM IF stages.

Now the tuning cords had to be restored. These were made of cotton or linen and had disintegrated long ago. Initially, shreds of string were lying randomly over the chassis. Lacking information of which pieces belonged together and where they came from, it wasn't possible to just replace the cords. I had put them in a bag to sort out later. The service manual from the the NVHR site showed how the tuning cords and the two cords to move the tone control indicator should run. There was one complication though: my KY585 was not exactly like the drawing in the manual. The guide wheels for the AM tuning cord did not correspond to the diagrams. I compared my radio to drawings of other Erres radios and concluded that Erres had made some design changes which made the string arrangement more like the KY595. The radio's serial number and the production date stamped on the original electrolytic capacitor suggest that it is from a later production series from 1959. Comparing the drawings, I was able to solve the puzzle and reconstruct the length and configuration of the tuning cords and springs and make the mechanism work.

Then I cleaned the diffusion screen and put it back.

Replacing the tuning scale presented another challenge: the rubber grommets holding the glass around the volume and tuning shafts were dried out and crumbling They had broken off when I removed the glass. Reusing them was not an option. I found two replacements, made of PVC. I attached them to the frame. Using a piece of fishing wire, I eased the flange of the grommets through the hole in the glass. I reconnected all eight wires of the tone controls, cleaned the knobs and mounted them. I also replaced the EM84 tuning indicator valve, that was working good but looked burned. After this, the chassis was looking great and working fine.

Now I had to take care of the cabinet. The baffle was already looking well with its fresh new cloth. But the front of the cabinet was chipped and the ornamental rods were corroded.

I was still wondering what had damaged the front so badly. When I took a close look of the corroded “golden” (actually varnished brass) ornamental rods, I noticed a 1 mm round hole that only a pointed object landing with impact could have made. I concluded that this radio must have been sitting somewhere near a dartboard in a damp barn, and that several stray darts had landed on the front, speaker and tuning scale glass.

Time to repair the damage and repaint the front. First, I needed to remove the brass rods. Each of them had four or five brass tabs soldered to them, that protruded through the front and were kinked behind it to fix the rods. I straightened the tabs to release the rods, which was not so easy because they were sitting in awkward corners. I polished the rods and resoldered some of the tabs that had come loose through my actions.

Polishing made the rods shine again. Their lustre was protected by a layer of spray varnish.

I sanded the front of the cabinet and filled the chipped spots in the painted area with car paint filler. Then sanded again. I carefully masked the parts that needed to remain brown. I found a semi-matt spray paint with the right color and applied the paint. After removing the masking tape and paper, while the paint was still soft and easy to remove, I trimmed away the uneven borders where the paint had crept under the tape.

The result was reasonably satisfying so far. Using a felt marker with golden ink, I accentuated the double chevron Erres logo and the ornamental stripes on the front. Using a black marker I made the “ERRES” brand name stand out again. Looking quite good.

I mounted the baffle and slid the chassis back in. Then put the bottom and back panels in place.

This restoration took a few months, but the result was fine. A clean looking radio that was playing well.