Moonraker Sales

I am recommending Moonraker to all my valued customers that have been phoning me to purchase radio products.

Click on the images to go to Moonrakers website.

This month's news

Silent Key Sale

Ofcom Amateur Radio Licence, Notice of Variation

FT101E restoration and repair

A picture of me in my workshop working on a FT101 restoration and repair, which is going well.

Fake Transistors

We have been receiving a number of radios with failed Fake 2SC1969, 2SC2166, and 2SC2312 transistors installed into them; these transistors work intermittently for a short period of time giving a power output of about 1 Watt and then failed causing no RF power output.

The 2SC2166 had the bias pot turned all the way up putting 2.5v across the Base-Emitter junction was not conducting Collector Emitter and still measured correctly when I removed and tested it when clearly it should have been blown.

If the printing on the transistor is of poor quality, not straight, and to small to read  then it's going to be a poor quality probably Fake transistor.

Fake transistors current gain

Another indication that your RF transistor is Fake is seen if you measure the Current Gain (hFE) on a transistor tester.

For the 2SC2312 the data sheet states the best current gain is 90-180 with the “DD” ident, but you will normally see the 55-110 ident “CC” with a measured gain around the 90-105 in used transistors found in CB and Amateur Radio equipment.

The Fake 2SC2312 transistor shown above has a current gain of 262 which is just impossible for this RF Power transistor; clearly whatever is inside the package this is not a 2SC2312 transistor and is more likely to be an audio power transistor which is just going to get hot and not produce a lot of power at RF frequencies.

MRF 477

This transistor is not what it claims to be because it should have a minimum gain of 20, and a typical gain of 70 according to the data sheet; this one has a gain of 6.

It is meant to have been made by ON semiconductor, but they have never made an MRF 477.

I also notice that a lot of the transistors I see that don't work or produce very little power output all have a letter "E" inside a circle in the centre of them.

Genuine Mitsubishi Power Transistors

Failed Capacitors

Failed Capacitors can let go at any time, and in rather a spectacular manner which is why you need to get your radio service regularly to avoid this happening.

You will notice that the Capacitor from the FT901 has a dent in the top case which occurred when it exploded and slammed into the regulator board which is located in front of it shorting out its circuitry.

Kenwood TS 50

This second Kenwood TS50s I have seen in the last few years in the workshop, when they are working they are a very good example of small mobile Amateur radio HF transceiver.

Unfortunately by the time that I get to see them they tend to be very much worse for wear; the first one I repaired had 34 separate faults spread across the whole of the radio, fortunately the radio had not been screwdrivered so it was just a matter of finding the failed components and replacing them.

You have to be aware of fake Chinese components for these radios because they just don’t work, and this is an all surface mount radio so unless you're happy with a hot air re-workstation and a fine tipped soldering iron working on these should be left to the professionals.

Kenwood TS-940S

This came in with the reported “dots” on the Display which is the PLL out of lock problem, but when I took the radio cover off the power supply had completely blown all of its components off the board in into the radio. The power supply boards are no longer available ether new or on the second hand market so decided to completely rebuild the power supply from scratch. This repair took over a year with having to source some of the components internationally and for the components that are no longer available finding equivalents components that were still available. Once the power supply was operational I found that the fan control circuit had failed so a rebuild of the fan control circuit, a service of the fan itself and I lowered the fan turn on temperature to 30 °C to help to keep the radio cool. I moved on to repairing the negative voltage inverter which had also stopped working.

The TS 940 also needs it bulbs changing from time to time, as well as the backup batteries for the Clock and the Micro processor, and a modification to the AGC circuit if the meter (Pegs) slams hard onto the end stops when you turn the radio on and off.

Kenwood TS 850

I have been repairing a few TS850’s, all of which have had leaking capacitors on the DDS board and other problems on the DDS board unrelated to the leaking of the capacitors.

I am very good at getting the surface mount capacitors off the board without ripping the track off, but you still have the problem of repairing the corrosive damage that has been caused and if you are really unluckily the DDS chips themselves which also fail if the acid shorts them out.

The IF filters have failed in a few of the radios I have repaired as well, and the Transmit/Receive switching can from time to time can burn out for no obvious reason.

Standard C8800

The picture above shows what happens when the electrolytic capacitors leak onto the printed circuit board or a radio transceiver.

The bubbling you can see is your copper tracking been eaten away and once you clean it up you will find you have no tracking any more.

Kenwood Tl-922

During the winter nights there is nothing better to look at than the warm glow of a pair of 3-500ZG with the higher plate dissipation the plate doesn’t glow red when you are transmitting.

Please don’t try this at home; several of the safety features have been removed to allow me to take this picture, and the 3.2KV on the top of the valves will kill you if you touch them.

Kenwood Tl-922

The picture above shows the final amplifier test into an oil filled Cantenna dummy load.

Kenwood TS 120S

This radio came in with a reported problem of being rather deaf, after some TLC it is now up and running.

Yaesu FT 847

This is an HF/6M/2M/70cm transceiver, which works very well out of the box; it is different from other radios of its type having an antenna socket for each of the groups of bands. The picture above shows me testing the radio on my local 70 Centimetre repeater.

I have read a lot about what radios can or can’t do after they have been wide banded, and to be clear just because you can get the radio to tune to a frequency it may be happy to receive on that frequency but there is a good possibility that it will be very unhappy trying to transmit, as is shown in the picture above the 70MHz band which uses the 50MHz (6 Meter) low pass filter will receive without any problems, but only transmits 10 Watt on full power which should be closer to 100 Watts.

Yaesu FT 767GX

This is a FT767GX with the 2 meter and 70 centimetre modules installed in it; It has taken a few weeks to identify why the ATU was not tuning at all, and the SWR wondered about while it was enabled, and the modules in the back reported to be transmitting 10 Watts but in fact they were only producing 1-2 Watts.

This radio also suffers with the switching diodes failing causing also of interesting faults, the cooling fans go noisy and need servicing, and the main tuning stops travelling in any direction when the tuning knob is turned.

Yaesu FT 757GX II

I have been having a lot of new faults with the FT767/757 radios I have been looking at recently, problems with the Phase Locked Loops (PLL) going out of lock, and mixer components failing. This 757 came in with a collection of strange faults including cracking on AM, No transmission on any band or any mode, and the meter lamps had failed. This is of course a complete departure from the well documented diode failure these radios suffered from in the early days.

Yaesu FT 757

I have spent a lot of time repairing the Yaesu FT 767 radios, and one day a FT 757 turned up for repair, it had No Receive, No Transmit, and No noise out on FM.

After inspecting the radio I discovered that something very strange had happened to this radio, with the Transmit and Receive 8v supplies being present in both transmit and receive, the switching diodes had also gone, but I expected that this is a common problem with the FT 757 modes of radio.

A collection of additional components had been found on the bottom of the board RF Board, and PA Board but didn’t appear to perform any useful function and so they were removed and the radio was restored to factory defaults.

Some thirty separate faults later and being realigned because someone with a screwdriver had had a go as well this radio is again up and running.

Yaesu FT-One

A 1982 Yaesu HF Set which turned out to be one of the longest repairs I have ever taken on, this radio was not transmitting the full amount of power expected and worse still was not operating on the same frequency as displayed on the frequency readout and it also changed as you changed modes as well.

Yaesu FT747GX

This radio was off-frequency and the main tuning control was so worn that it jumped all over the place.

Yaesu FT 840

This radio came in with a flashing LCD, a classic PLL Out of lock indicator.
The problem was traced to a failed power supply on the Local Board which included a number of failed electrolytic capacitors, burn tracking and pc board, and numerous failed solder joints.
After some careful and time-consuming replacement of the failed components and the repair of the printed circuit the radio was returned to an operating state.

Yaesu FT-707

This radio has received a general repair and test to get it  back to a fully operating state.

Yaesu FT-707

This is another FT 707 which has received the replacement of the tantalum capacitors which have a nasty habit of going short and exploding, and while doing a Transmit test thinking I had replaced them all there was a cracker-ling sound and the magic smoke appeared from the PA unit. A tantalum which was not on the circuit diagram had let go, and as you can see from the image above gotten very hot burning the components around it.

Yaesu FRG 7700

This receiver came in with the normal problems of the band switch not working all the time, and after inspection it was noted the power supply board had burned due to bridge rectifier problems and the PLL was off-frequency. The volume and band switch controls were cleaned, and the receiver board was recapped, which restored the expected performance of this receiver, the power supply and PLL board was recapped to remove some very old capacitors.

The above picture shows the receiver under test listening to the local radio station.

Yaesu FT101ZD

This yaesu came in with exploded high voltage capacitors on the Rect-B board, and very poor transmit and receive performance along with the normal problem of most of the display bulbs had blown.

After a new set of electrolytic capacitors were installed on the Rect-B board, and a problem with the FM board, and RF board was resolved which was causing the loss of TX and RX on all bands.

The radio was tested on transmit and receive, it was found that the ALC circuit also on the Rect-B board had failed as well; being only a small circuit all of its components were replaced and this restored the ALC function.

The power supply voltages were checked to see that they were correct, and the final Bias was set to the correct value; the 6v supply to the VFO was checked for stability.

There is nothing worse than having your radio tune itself up and down the band because the 6v supply is not stable.

The crystal board crystals coils were adjusted so all the crystals produced the same amplitude; I am not sure if the settings had drifted over time but some crystals were very low.

Yaesu FT101ZD

This yaesu came in with a note saying it keeps blowing fuses, there were several shorts in the power supply, but unfortunately it was to late, it appears the transformer insulation has gotten hot and leaked out, see the picture above.

Icom IC-740

This radio came in without any transmit output power, it was discovered that a number of faults had developed over time, and were successfully repaired after which transmit on all modes was restored. The normal checks were also performed as well as the On-Air test.

Icom IC-751

This radio came in to the workshop with no display, no receive, and no transmit, and turned out to be one of the longest repairs I have undertaken. It initially looked like the battery had gone flat which is a common problem with these radios, but it turned out to be loads of problems with various internal power supplies, and the PLL was also out of lock. The finishing touch to this repair was a new meter high brightness LED, and some new screws in the top case cover.

IC 745 Inverter

This small circuit powers the display in the front of the radio, it does have a habit of stopping working and I have repair quite a few of these circuits, but this one has let go in rather a spectacular manor, with Q4 splitting down the middle, and some burnt tracking on the bottom of the board.

Icom IC718

A friend called in to have me fit his CR-338 high stability crystal into his Icom HF radio.

Icom IC-810

This is the second visit of this radio, it came in several years ago with the standard no transmit on 70cm’s but this time had no receive.

Like so many of the problems with these ageing radio's capacitor failure is the root cause of the failure and once replaced normal service is resumed.

Icom IC-735

This radio arrived with no transmit on any band or any mode, the display lamps had blown so you couldn't see what was going on and the controls were so stiff I don't think they had moved in years, on the plus side receive worked without any problems.

After a lot of work on the PA unit which had both the final and driver bias control faults with the finals having so much bias

that every time you keyed the radio the power lead fuse blew, after the PA was repaired a lot of TLC on the rest of the radio brought it back to a fully functioning condition.

The picture above shows the radio transmitting at full power on FM after the completed repair.

Tokyo Hy-Power HL-45

I have just changed and re-biased the Power Mosfets in this Tokyo Hy-Power RF amplifier, this is the first one I have done as there are not many of these quality products about these days. The picture shows the amplifier transmitting 40 Watts output for 2 Watts of drive.

Microwave Modules 144/30 LS

This amp came in with no power output, the transistor tested alright, but the bias current was set to high it was difficult to believe it had ever worked. I turned the bias down to a more reasonable value, further investigation revealed a failed component which was replaced and normal transmit function was restored, and the Rx amp was also tested to confirm that it worked.

AOR AR5000

This receiver arrived with a unable to receive on AM or
SSB fault but FM is received alright.  You can see from the signal meter in the picture that after a surface mount component repair the receiver now receives AM without any problems.

Drake R8E

This radio came in with a no receive fault, after performing a quick inspection I found two of its electrolytic capacitors had leaked electrolyte all over the corner of the board and was eating the top tracks off the board. This was quickly cleaned up before the problem got any worse. The receiver had several faults which were identified once the receiver could be operated in safety. It was not possible to perform the normal On-Air test, so I had it on in the workshop tuned to Radio Caroline.

Lowe HF 225 Receiver

This receiver came in with no display when it was turned on, after a close inspection it also appeared that it required the replacement of its electrolytic capacitors.

Trio - TR9000

Here is an example of a Trio Multi-mode radio from the early
80’s, this radios being mono band incorporates  a three pole band-pass cavity filter which filters out the out of band noise which we are all suffering from these days much more effectively than “The rig in a box” is able to do.

Trio TR-7930

This is a 2-meter mobile transceiver from the early 80s, it came in with a range of problems including the inability to enter any frequencies into the radio via the keyboard, all the lamps had blown so you could not see what was on the display, and there were a number of failed capacitors.

The radio pictured above is the second one that came in the same consignment, but is somewhat worse for wear, apart from the normal problems the radios PA block has blown so it only transmits 15Watts as shown on the power meter, and someone had tried to change the CPU and had got into difficulty while doing it. This repair took lot of time but keeping an old piece of equipment going is well worth it.

Trio 9R-59DS

This radio came in with reported frequency drift problems, but turned out that it had not been serviced for may years and a significant rebuild was required. This radio was produced between 1968-1969 and at 52 years old is one of the oldest receiver's that I have repaired.

Bottom view of the Trio 9R-59DS.

Those power supply component's next to the mains transformer which are uncovered with bare wires can give you more than a tickle if you touch them by mistake.

Top view of the Trio 9R-59DS

They just don't make them like they used to with all those thermionic valves.