[R-390] Possible SP 600 Reman/upgrade parts kit
Perry Sandeen
sandeenpa at yahoo.com
Wed Jun 4 15:36:14 EDT 2025
List,
Sorry for the long post but I needed it to make my thoughts clear.
There are many fine upgrade ckts for the SP-600. There have been numerous warnings about the "BBOD's" for years. The problem is that the other fundamental parts such as resistors, ceramic caps, wires and electrolytic caps are all problematic in their own ways. The rebuild kit I'm proposing is a complete replacement of all CC resistors, filter caps, wires and SS replacements for the B+ and negative C-.
This will provide a stable base on which to do improvements W/O the problems of basic circuit drifting.
I'm considering making a passive parts reman/upgrade kit for the SP 600 that consists of aboot 108 new 1/2W and 1W 1% MF resistors for complete replacement of all but the alternate crystal osc. Included are 20 .01/1Kv and 6 .01/100Vdisk capacitors, replacement PS filter capacitors, Corcom AC input filter, CL 80 surge limiter, MOV 130V, wire set of six different colors to replace wire harness, NOS 7 pin tube socket for a 6AQ5 conversion and more. Because of cost, mica caps are excluded.
This parts list was compiled from a JX-21 ski. Because Hammarlund was always "tinkering" with the SP 600 ckt. your model may have slightly different resistor values.This isn't a Heathkit. Some, or maybe more ingenuity, may be needed.
The kit parts include those needed to do the Chuck Ripple audio output upgrade.
I'm attaching a PDF of all that's included of all that I'm planing to supply.
Electrolytic caps are Nichicon 105C 10K hour rated. Resistors are mostly vishay/dale and other quality brands. NO Yago or other bottom of the barrel brands of parts.
The price for the kit will be $100 plus shipping from 29325. A great deal of the high cost is the need to use 1W MF resistors mainly in the RF module as it's heat is to high for 1/2W MF or CC units. A copy of the JX 21 annotated ski will be included as well as Andy Morrer's SP 600 model tutorial.
This price is far less than an individual purchase as most parts have a good price break at 10 or move.
The goal needed for the project to be possible is at least 7 kits although I'll be buying for 10kits
For this to happen I need at least 7 orders and a $25 non-refundable deposit if you order a kit and then change your mind. If I don't get a commitment for seven, your money will be refunded.
I'll set the deadline for response for one month or so.
73,
Perry KM6FQV
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