Tech Note 2 Stringing the FM dial cord on the ICF-6800W
(last rev September 2009)



1. PREAMBLE

OK, the PLL is humming like well oiled machine by now... Time to put the radio back together. Of course, during disassembly the FM dial cord arrangement fell apart. No problem one thinks... all the stringing is well documented in the service manual SM. Oops... not this one...the documented stringing on page SM 35 uses 1 cord...but production radios use 2 (at least the serial numbers I have seen). Get ready for a serious puzzle if you need to reverse engineer this one...this page has some hints.


2. STRINGING THE DIAL CORDS - EASY WAY

Available are 2 cords: one (A) has a longer, thinner spring and is longer in length and another cord has a fat spring and is about 5cm to 10cm shorter (B). You can string them independently. Direction left/right from top as you have the front of the unit facing towards you.

a. Cord B

i. This is used to connect the dial drum with the capacitor drum.
ii. Both spring and eyelet attach to the capacitor drum, to the two hooks on this drum. The guidewheels at the sides are not used.
iii. Turn the tuning cap fully counterclockwise and position the cap drum with its opening to the left as seen from the top. Position the dial drum opening down. Attach the eyelet to the top hook of the cap drum. Immediately go right, straight down to the other drum. Go round 90, attach to the hook on the dial drum, go around, then straight up at the other side. Go around over the top of the cap drum. Attach the spring to the free hook on the cap drum.
iv. You should end up with both drums smoothly running in tandem.

b. Cord A

i.
This is used to connect the dial drum-capacitor drum unit as above with the dialing shaft.
ii. Both spring and eyelet attach to the dial drum, to the two hooks on this drum. The guidewheels at the sides are  used, hence the longer length.
iii. Start with the dial drum opening down. Attach eyelet to hook. Go to the left, and around to the tuning shaft (attack from right). Make 3 turns, then go to left guiding wheel. Go up to cap drum. Run cord over cap drum to other right guiding wheel. Immediately run to the opening of the dial drum and attach spring to remaining hook.
iv. Everything should run very smooth over the whole range, if cords tnagle/block try again.... Cord A is easiest if you do everything without the left guiding wheel, and then add tension by running cord over this wheel.


3.
STRINGING THE DIAL CORDS - FACTORY WAY

Available are 2 cords: one (A) has a longer, thinner spring and is longer in length and another cord has a fat spring and is about 5cm to 10cm shorter (B). You can string them independently. Direction left/right from top as you have the front of the unit facing towards you.

This one has cord B (cord 1 in figure) ends on dial drum, and cord B ends on cap drum. A service manual suplement exists with details (thans Carel Kuijer)






4. ALIGNMENT

The dial scale itself is to be positioned to a known frequency. You can move it around by hand.


5. DOCUMENTATION

One can find decent scans of the service manual on the web (Mauritron original). For this problem, they don't help - they are even confusing.

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