TS-930S Upgrade Project

My current multiband PSK rig is a TS-930S/AT. This was gotten for a reasonable price, considering it has both CW filters fitted. A little extra R&R was required to get it into tip-top shape, then in the lineup it went.

Sunday night saw me reading while laying on the ham shack/living room couch. (Yes, I live in a Man Cave.) Sunday night also bore the scent of Factory Smoke(TM) escaping from somewhere in the radio lineup. I quickly localized it to the '930, which was shut off then unplugged from mains power.

Next day I took the top cover and PS fan assembly off the rig, looking for areas of potential damage. I found nothing, but the AVR Board stunk a bit. Time for repair - or outright replacement.

When I bought the rig I'd studied this product: https://k6iok.com/order-now-store?ol...int-20a-supply

Of course, I missed the Christmas discount and ended up paying full price for the kit...but given the fact the stock '930 PSU is a questionable design to begin with - and the PA brick transistors are Unobtanium at this point - it made sense to replace the works with something less prone to destroy the PA devices if it fails.

A quick check of the PA with the stock supply powering the radio showed no damage, but I'm not going to risk potential destruction by running with the stock PSU. Conversion details to follow when the kit arrives. Future upgrades to the rig look to be an Inrad roofing filter (w/ AM RX bypass when run in "Wide" mode) and maybe a Piexx CPU replacement.

I'm also beginning to get the hankering for another TS-940S/AT, as I really liked both the ones I had...except for the time-bomb PSUs. They share all the evils of the '930's setup. 'IOK also offers a conversion kit for those rigs. No affiliation, just a (hopefully) happy customer.

PSU upgrades

The Compudigital kit arrived a few weeks ago. Jeff, AK6OK does a very good job with their instructional videos - but one can always improve on things.

When removing the OEM supply, I didn't hack it apart (per the instructions). I carefully removed all of it as a unit, and as of disassembly it's fully functional - with the exception of the Zener/dropping resistor arrangement in the PS fan cage. That design is mighty questionable from the outset, though W6NL and others have come up with reliability improvements. I decided to replace the entire supply section rather than rebuilding Kenwood's circuitry.

First order of business was modifying the fan assembly. I replaced the Kenwood part with a 12VDC brushless 70mm computer fan, set to blow inwards towards the supply. The mounting holes in the fan cage allow for an exact fit. A matching 70mm grill was added on the back of the cage, and the mounting hardware was secured with blue Loctite.

All the OEM power-supply circuitry was removed from the cage and a piece of 1/2" aluminum angle (cut to fit in the cage) was secured by spacers, washers and hardware with Loctite applied. A clearance notch for the fan was cut, and the OEM top cover retainer bracket (shown in the yellow oval below) was modified by removing part of the material below the original mounting holes. A new centrally located mounting hole was drilled then the bracket was installed with standoffs, machine screw and locknut. This bracket does double duty as it retains the Quint switching supply and keeps it from bouncing around inside the case. Minor adjustments to spacer length may be required to get yours to line up with the cover holes.

The fan cage has room for additional filter capacitors for the various supply voltages, should they be needed. Thus far, they haven't with my '930.

Attachment 16139

Compudigital's PS upgrade kits come with a replacement AVR board and a piece of Snap Track with which to mount it. The videos state to mount the Snap Track vertically, and this won't work as the top cover's control access door hardware will interfere with the assembly. Mounting the unit horizontally fixes the issue. A raised section of the chassis will interfere with the left lower section of the Snap Track, so the latter is clearanced with a rotary tool. Remove 1/4" x 1/16" of material and the fit is exact.

Jeff states to use a silicone adhesive to secure the Snap Track. I borrowed from my motorcycle toolbox and employed "Yamabond 5", a non-rigid permanently drying adhesive. Mounting horizontally allows the use of two surfaces by which the Track is secured to the chassis, so apply adhesive to both. Allow to dry overnight.

Attachment 16140

Note the "+28V PA Power" line. Instead of using the supplied bullet connectors, I dug into my motorcycle stash and found the appropriate Hitachi bullet connector hardware plus boots. This is the type Kenwood used for the PA connections in the original design. Compudigital's PA power leads are pretty decent size and a little dielectric grease helps the boots to slide around on the wires.

(Note: The Hitachi bullets plus a lot of other useful motorcycle-specific connectors can be found at Vintage Connections, though I've seen them popping up on eBay in recent times.)

The new AVR board has a 4-pin inline connector which permits one to continuously run both of the radio's fans at 9V. I used bullet connectors from the kit to interface the new PS fan to the appropriate lines, and used bullet connectors from my stash (which are a different style) on the PA fan power lines, differentiating them. At this point I'm using the OEM PA fan and thermistor-based control setup. Should this fan ever fail to start, I have another 12V 70mm unit ready to replace it. At that time I'll wire it to the constant-on supply lines.

Also seen in the picture below is the Quint switching supply and the PS fan cage, with modified cover attachment bracket.

Attachment 16141

I routed the AC wiring (inside sleeving) along the side of the supply and used a wire anchor to secure the leads to the chassis. Note that Kenwood fuses the neutral side of the AC line....BAD! After removing the AC voltage selector switch and bracket, I rewired the area so that the hot side of the AC receptacle goes to the rear fuseholder terminal and the front one goes to the AC switch (via the wires in the picture below). It's a bit fuzzy, but you get the idea of the routing path. Another chassis hole opposite the wire anchor is used to secure a small "L" bracket, which helps prevent the new supply from walking around.

Attachment 16155

Here's the supply with the regulator board powered up and operating. It looks cool and it also runs cool...a lot cooler than the OEM supply, even when the latter has has its cooling fan modified for constant-on operation. There are several status lights on the board to let the user know that all (9v, 12v, 15v, 21v, 28v) output circuits are operating correctly.

Attachment 16156

Meter Lamp upgrades

Compudigital offers a LED meter lamp kit...in either white or blue. Jeff threw one in my kit - gratis - due to an order delay. The PCB artwork shows a 1.5K dropping resistor in series with each LED, and a diode of some sort in series with power feed to the board. What was installed on my board was a 510 ohm dropping resistor at each LED spot, and a wire jumper where the diode was originally supposed to be place.

Way too much current flowing through the assembly when hooked to the TS-930S Meter Lamp (28v) supply, as things were getting hot upon power-up. I reworked the board, substituting 1.3K resistors and a 1N4002 diode for the OEM parts...

...and THEN I read the (furnished) manual. The kit was set up for the TS-940 and had components installed for its 12v Meter Lamp supply. The user is instructed to install a 1Kohm resistor in series with the Meter Lamp lead when the unit is installed in a TS-930.

Doh! :doh:

Instead of using the supplied grommets for the LEDs, I carefully removed the incandescent bulbs from their green rubber holders then gently positioned the new LEDs into them, while they were installed in the meter lamp bracket. Final adjustment of position and aiming can be accomplished by slightly moving the board in or out of the rubber holders.

I like the look better than the OEM yellow. Fans of the Orion/Orion II will immediately relate to the appearance.

Attachment 16157

Quote:

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Originally Posted by N8YX

...and THEN I read the (furnished) manual. The kit was set up for the TS-940 and had components installed for its 12v Meter Lamp supply. The user is instructed to install a 1Kohm resistor in series with the Meter Lamp lead when the unit is installed in a TS-930.

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Manuals... who reads manuals these days ?

AGC Mod

This one was stolen from W6NL (article in hyperlink below). It puts a germanium diode (1N60 used here) across D125, with the new diode's anode to D125's cathode. The purpose is to prevent AGC de-sense on the first incoming dit of a strong CW signal. The diode is located under the accessory 455KHz CW filter, which if installed must be removed to perform the modification. The carrier board is then installed "backwards" so the filter pins won't impinge on - and possibly break - the new diode.

Added diode:

Attachment 16167

455KHz filer re-installed "upside down":

Attachment 16168





https://www.kkn.net/~k5tr/ts930fix/w6nl930.pdf

DIY AM Filter

My rig didn't come with an accessory AM Filter (YK88-A1) but it did have the filter bypass board installed. This board uses the 1st IF filter (the so-called "roofing filter") to set overall AM selectivity and merely acts as an inter-stage coupler. I had been (unsuccessfully) looking for a YK88-A1 but had a couple YK88-As in my junk box...along with a spare bypass board. I decided to have a go at making my own filter assembly.

Here's a top view of the bypass board. All circled components must be removed:

Attachment 16169

Use a good temperature-controlled vacuum desoldering iron for this task. You might be able to use solder wick and a pencil iron to extract the components but watch the heat.

Next, use a Dremel tool and small burr to cut a relief in the copper foil for one of the filter "hot" pins. Scrape the solder mask off the indicated areas, tin them and solder a YK88-A onto the carrier board. Then make the indicated jumper connections:

Attachment 16170

Install the completed filter assembly in the correct spot:

Attachment 16171

Before buttoning up the case, check your work. Note that this filter is in-circuit when the front-panel NAR button is "out" and the Mode Selector is set to AM; the 2.7KHz SSB filter is used when the NAR button is "in".

The response curves of an -A and an -A1 may differ. I detect a bit of asymmetry in the pass band as I tune across an AM signal but consider this to be a feature rather than a bug: It's easy to center the tuning then use the rig's RIT as a pass band tuning control of sorts, moving the signal to one side or the other of the filter skirt to minimize interference and improve readability.

Very nice. But that radio is too modern/crowded for my liking. I prefer my Corsair II for tinkering.


For those who don't know, you can measure the bandwidth of the demodulated signal with the help of a sound card and some free software:

https://www.qsl.net/pa2ohh/12audiosa.htm

https://www.dxzone.com/catalog/Softw...rum_analyzers/

There is stuff for Android as well, in those cases you can even use the phone's microphone to make the spectral analysis.


73,
Carlos

You ain't seen "crowded" yet! :lol:

The next part of this project details construction and installation of dual roofing filters and the switching assembly used to activate them. Of course, as luck would have it I found a YK-88A1 on FleaBay the day after I posted the DIY AM Filter mod...

Got any photos of the MARS mod to the digital pcb? Thought I saw one online someplace.

There's a jumper pad set on the bottom of the board. I think it's J3 but will verify that (with an email I have from Piexx). You have to bridge the pads to activate it.

Ok I confirmed its in there, I see the jumpers to the IC chips. This is the stock digital board.

Stock digital board requires a bit more work to get general-coverage TX.

Mods.dk and a couple other sites have the info.

I have one from a 5mil S/N '930S. If you want the thing, I can send it out.

Sure. I guess its a better design than the older serials? Same number of connectors?

Was curious if u ever did the alignment on your 930? If so what were the things that
you found needed adjusting?

Quote:

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Originally Posted by KA2PTE

Was curious if u ever did the alignment on your 930? If so what were the things that
you found needed adjusting?

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The only outstanding item I have to address is the ALC indication. It's way off kilter at the moment though the rig doesn't distort on TX.