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Model 86 Help
#1

I am currently trying to work on a model 86 Neutrodyne Plus. I am deciphering the schematic. I need help and tips on rebuilding the capacitor box mounted on the top of the chassis. Any tips from anyone who has gone through this would be VERY welcome! There is also another capacitor box that per the schematic appears to contain two .5 mfd caps. No evidence of voltages given for them or the others. Right now the set will actually come on and play but appears to have alignment problems (whistling and motorboating on strong stations, other issues) Thanks! [/font]
#2

I did an 87 awhile back. It's kinda messy and smelly. Mark all of your wires so you'll know where the reconnect them after you've replaced the caps. Remove the can from the chassis. Heat it in the oven at 175 or so to loosen the tar. Then you can use a cork screw or a large eye bolt to screw into the caps and pull them out. Clean the can out. Solder new Mylars where the old ones were. Install onto chassis and wire it back up. Then you are in business! Voltage wise your looking for 630v jobs.
Wouldn't try to do any repair work on the set till after this is completed. Without the proper filtering and bypassing you'll be chasing your tail trying to fix it.
Terry
ps Welcome to the Phorum!!!!
#3

Good advice, Terry.

Your resistor color codes are NOT what the later standards were. Therefore you must be sure to trace where each one is in order to determine correct value in accordance with schematic. If it is like the early sets that I have worked on, most of the resistors will be out of tolerance and will have to be replaced.

There are several threads here about re-stuffing the cans. Several good techniques here!

Also note that there is a good a good article in the tech section here about by-passing the sp-ppg transformer, as they are often bad.
#4

Good advice Tom
I'll also mention that it's not uncommon for the RF coils to have open primaries. Easy repair by removing the coil from the set. Remove the open winding and rewinding with 50 turns of magnet wire. Number of turns is not very critical. Gauge of wire isn't either anything from 30 to 40G is fine.
Terry
#5

My gosh! Thanks so much for all of the helpful replies! I'll be back soon when I get into the model 118 I have stuffed in the corner! Special thanks to Radioroslyn!
#6

THANK YOU THANK YOU THANK YOU! Every bit of this information has been extremely helpful! The power transformer on this set has two voltage setting as well as 3 crumbly rubber wires leading from the switch to the transformer. setting is for 95 - 110 V or straight 110 V, it appears. Which setting is the best and I was going to shrink tube the wires to prevent having to break the transformer down. Any recommendations there as well?
#7

I found a instruction manual for this set. I have as well re-capped it and it is playing. The manual has stated the set will experience interference on strong stations without a good antenna or ground hooked up. The manual was right. After hooking a good section of solid strand hook up wire across the local and antenna leads, the set performed much better. However, I've not hooked up a good ground yet. The range switch and volume control, when used in tandem, will get the volume under control and stations coming in loud and clear. However, the volume occasionally acts as if it's working in reverse, and will pop and hum as if there is something still amiss. Any suggestions? When I place my finger on the ground lead, the volume drops a little. The hum reducer still works beautifully and will take most hum or noise right out of a station coming in.




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