Lafayette KT-200 Complete Rebuild
I picked up this Lafayette KT-200 4 band short wave receiver on eBay early this year. It was in fair to good shape but the original kit builder skills were fair to poor. I decided to completely rebuild the receiver, disassembling the receiver down to the original kit stage as shown in the pictures below.
The KT-200 is the American kit version of the Lafayette HE-10. There is a Japanese kit version, the “Trio 9R-4J” produced by “Trio”.
The receivers are basically the same. The KT-200 power transformer’s AC power connection can be set for 100VAC (typical AC voltage in Japan) or 117VAC by connecting to the appropriate transformer primary terminals. There isn’t an AC voltage level select switch like the KT-320 and HE-30 has.
I had to replace the ON/OFF volume control as the switch was bad.
The S meter is not original so I’m still looking for an original KT-200/HE-10/9R-4J S meter.
I replaced the broken Banana plug antenna terminals and repaired the speaker terminal strip by removing the RCA socket.
I have a reproduced KT-200 assembly manual which contains all the assembly steps and complete one page fold out pictorials.
Front view
Rear View. Note RCA socket installed next to the 3 tab speaker terminal strip. Also note the broken/missing Banana antenna sockets .
Top View showing all new tube sockets, replaced Banana antenna sockets, and fixed speaker connection. The new White ceramic tube sockets were found on eBay.
Since this picture was taken I’ve removed all of the tube hold down wire clamps, they’re not needed. The audio transformer’s secondary wires are very thin as they leave the top of the transformer. I applied Gorilla Glue to the wires at the point where they exit the transformer cord to provide more support (not shown in this picture). The audio transformer leads are very thing. I was concerned they could break so I cut the wires shorter then added 22awg solid copper wires to strengthen the wires. I slid correct color heat shrink tubing over the wiring and slid the wires through the holes in the chassis (not shown in this picture).
Update 28 Nov 2023
I do not recommend using those White ceramic tube sockets. The socket receptors where the tube pins insert and make physcal metal to metal connection do not allow for the tube to be fully seated in the socket. I had trouble getting all tubes seated in their sockets. I had trouble seating V3, the local oscillator tube, in its socket. I finally got it 90% seated in its socket for it to operate. At this point it’s too late to change the tube sockets.
Bottom view showing full wiring and component disassembly. The original multi tab terminal strips were cleaned and reused (not shown in this picture). Front panel switches and headphone socket were cleaned of wiring and solder. I reused the original mounting hardware as it was in good condition.
There is an error on the second page of the assembly instructions. I’ve documented the error in the complete assembly manual. If interested in the error contact me for details.
I could have used new individual 40ufd 350VDC axial lead capacitors to replace the original dual 40ufd capacitor but I wanted the rebuild to be original. So, I special ordered two dual 40ufd 350VDC insulated power supply filter can capacitor from Hayseedhamfest.com. I used one for this full restoration and the other is for the repair of a Lafayette HE-30 I have. The 3 terminals are oriented the same as the original capacitor (see above picture). The outside of the capacitor is encased in a clear plastic cover, same as the original capacitor. The special ordered capacitor fits perfectly in the capacitor clamp mount.
Update on point to point wiring
Point to Point Filament and B+ Wiring. Twisted Black and Yellow are the filament wires. Red is B+ wiring. I’m about 80% finished with the point to point wiring. There are 5 RG-174 coax cables that need to be installed.
Update on component wiring
I have 95% of the resistor and capacitor components installed. There is one and a half pages left to complete the assembly of the KT-200.
I was able to reuse some of the original resistors as I didn’t have those values in my new resistor part bins. I checked each original resistor to ensure it was within 10% tolerance. I was surprised, all of the original resistors I reused were all within “1%” of the resistor’s tolerance. The reused original resistors are Gray dog bone type resistors.
Click the picture to zoom in and out for a better close up viewing of the wiring.
The 5 RG-174 coax cables have been installed, connected, and tie wrapped.
Full Rebuild Complete
12 Nov 2023
The full restoration reassembly of the Lafayette KT-200 receiver is complete. I use 90% new components and 10% original resistors as some of the resistor values are not easily available today. I verified each resistor, original and new, to ensure their values were correct.
The filament wiring is Black/Yellow 18awg solid copper wire. The other wiring is 22awg solid copper wire. The large Black resistor on the upper left is R21, a new 2K 10W. I did not use C24, a 0.01ufd 600VDC capacitor across the primary winding of the power transformer.
I performed the 2 preliminary resistance checks in the manual. I replaced the original 2 wire power cord with a 3 wire grounded power cord. The manual’s 2 resistance checks passed. I then performed a thorough visual inspection of all connections to ensure there were no shorted leads, bad soldering, and connections that did not have any solder. All soldering issues were fixed.
A 3/4 amp fast blow fuse was placed in the fuse holder.
Final power up test was successful. The receiver came to life and signals were heard on the various bands when an antenna was connected to the rear Banana sockets.
Click the link below to watch my video of the working fully restored Lafayette KT-200 4 band shortwave receiver.
Update on the S meter replacement
I was able to find a few R390 1ma FS meters that fit perfectly in the front panel opening. I settled on the White scale meter, looks closer to the original S meter. The meter does not have an S Unit scale but rather tick marks between 0, 5, and 10. I added dual back to back diodes across the meter terminals.
I’ve placed an order for a replacement 500K pot with switch. The original pot was bad. The original pot with switch has a 6mm diameter shaft allowing the original knob to fit the control. I had a 500K pot with switch to replaced the bad pot but it has a 1/4″ diameter shaft. The original knob will not fit the 1/4″ shaft. I kept the original knob so when the new replacement control arrives I’ll replace the control so the original knob fits.
https://w5rkl.com/wp-content/uploads/2023/11/Fully-Restored-Lafayette-KT-200.wmv
The video link below was made with the dark scale R390 meter. The picture below shows the White scale R390 meter. The meter is as close to the original meter as possible without an S Unit scale. The meter looks much better than the Lafayette CB radio S Meter.
Replacement meter using an R390 Meter
