| VK5 HYBRID RADIO GROUP |
FT101B/E & FL101 RESTORATION This WEB Site is Devoted to Maintaining Hybrid ( Transistor/Valve
) All Information on this WEB page is copyright
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Tuesday 12th August 08 
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| FT101 MODELS Refer to the NW2M web site for further information on the models that were produced. SAFETY IS FIRST Please read the Safety information before attempting any repair or restoration. These Radios are Old. I don't recommend anyone attempting Repair or Restoration unless they have plenty of time & know what they are doing. The FT101 has some very old parts inside, & you may be better off trying to find a FT101Z/ZD, or TS520/820 Kenwood which look much better to restore. If you just have to have a FT101, then try finding either an FT101E or EE as they are a much better looking Radio compared to the older models. Many parts like trimmer capacitors, & trimpots will need replacing, so a full alignment will be required. I suggest that you evaluate the Radio carefully before going in too hard as it may not be worth the effort especially if the Radio is already in poor physical condition. The FL101 Transmitter is very similar to the FT101 so many problems & alignment etc can be assumed to be similar. The matching FR101 Receiver has some similarities in the circuitry to the FT101, but the chassis layout & boards etc are completely different. Refer to the FR101 Receiver restoration page. ( does not exist as yet ) First thing always is Safety. Check the power cable condition & fuse. The Mains fuse should be a 3Amp 3AG fast blow in the FT101 when using on 240 volts, or 5Amp 3AG FB for 117 volts. I am yet to confirm this as I always understood that mains fuses should be Slow Blow due to mains surges when switching on the appliance. I recently heard a story of a Ham getting an electrical shock off the rear of a FT101B when he picked it up. Someone had added an external relay on the rear panel with live mains wires that was probably used to power a linear amplifier. Check that you have a proper 240V mains earth from the chassis to the earth pin on the mains cable with a multimeter. Many older Radios have never had the earth connected in the Jones plug so check this. Powering it up I found the receiver to be quite deaf, especially on the 40M & lower bands, but the S meter indicated a signal of S3 noise without an Antenna plugged in. Plugging an antenna in made very little difference in the noise from the speaker. I had read many things about blown 3SK40M RF amplifier Fet's which are not easy to find these days. On examination of the RF Unit ( PB-1181 ) there was a small vero board soldered to the top of the RF unit. It looked like an extra RF amplifier, & the wound coils indicated that it was probably for 10 or 11 meter bands. I removed the board & fixed the RF unit back to original, & plugged it back in & things seemed much better on the lower bands. My FT101B example here has some corrosion & the appearance is quite poor due to front panel paint damage. The paint around the ( White Rocker type ) power & heater switches has chipped & cannot be repaired without it showing up. This was not an issue on the later model FT101E/EE due to the use of different switches, ( Black lift type ), & factory supplied plastic over the front panel. The first thing that we do with any Radio Restoration after we have checked that the Radio is safe, is to give the outside cabinets & front panel a basic clean to get some of the grime off of it. If you cut yourself on the cabinet or chassis it can be a potential to cause infection especially if the chassis has Nicotine stains. A more thorough clean can be done if required by removing the knobs & using a foam glass cleaner, ( CRC Glass Cleaner ) & lint free tissues to clean without damage to the paint. This type of cleaner tends to put the dirt out & will not damage the paint. I also removed the black front plastic cover & outer grey metal trim & fully removed the remaining plastic that was pulled off of the front panel. The Outer grey trim can be easily repainted if required before reassembly. I then started inside the Radio. A large number of faults or intermittent's can be traced to dirt in pots, switches, & relays. Use a suitable contact cleaner lubricant,Electrolube EML & spray inside all the pots, trim pots, & switches. It is also suggested that you remove any covers over relays & try & clean the contacts. Make sure that you use a lubricating cleaner specifically designed for the job else you risk permanently damaging pots. Be very careful with front panels, pots, switches, knobs etc as there does not appear to be any spare parts available from Yaesu if you damage or break them. The good news is that there appears to have been huge numbers of these sold, so there may always be a wrecked Radio around for parts.
I removed all the plug in boards, relay, & Valves & cleaned the chassis with a brush & Vacuume cleaner. I then sprayed all the green chassis sockets with contact cleaner lubricant, & also cleaned along the boards connectors with cleaner & cotton buds. I removed the relays top cover & cut some thin strips of paper & sprayed some cleaner on the paper & used it to clean the relays contacts.
POWERSUPPLY It is best to replace the electrolytic capacitors on the PB-1314 Power Regulator board. Be careful & check that all voltages on this board have discharged before removing the two screws in the board from the Radio. The new capacitors are much smaller than the original, so the leads have to be bent to fit the pitch of the original holes in the board. I use Dow Corning 738 RTV sealer to secure the capacitors in place. While you have the board out, check for any bad solder joints & spray the trimpots with contact cleaner lubricant, although I would replace them. Also check & clean the board connector. Also check the condition of the red ( Greencap ) type capacitors for cracks in the outer casing as I have found a few cracked ones. The 6 terminal MFC6034A regulators are an obsolete part & can be replaced with a adjustable LM317T type regulator. There is plenty of room to fit the required parts around a LM317T when the MFC6034A & surrounding parts are removed from the board. Find the data sheet on the WEB for the LM317T, & construct the adjustable voltage regulator circuit using the existing 6 Volt ADJ trimpot on the board. It is suggested to replace the Zero set & 6 Volt ADJ trimpots with modern 25 turn trimpots to more accurately align the settings. You will have to drill the board to fit the new trimpots.
The above Image shows the PB-1314 Power Regulator board. The Electrolytic capacitors in these old Radios should be replaced as they are commonly leaky or dry.
CAPACITOR REPLACEMENTS 1 x 22uF 160V ( Use 22TKR350 ) 3x 22uF 250V ( Use 22TKR350 ) 2 x 1000uF 16V ( Use 1000TKR25 ) , 2x 1000uF 25V ( Use 1000TKR25 ), 1 x 100uF 16V ( Use 100TKR25 ). Refer to the bottom of this page for FT101B/E capacitor Kits. If you have low HT when in TX mode always suspect either one or both of the main filter capacitors ( 100uF 500V ) could be open circuit. I have only had one Radio with this problem that caused very low output power. Don't skimp & use 450 Volt capacitors here as they are too close to the voltages normally measured & could explode. I don't at this time have a replacement source for these. I then checked the PB-1076 Rectifier Board. There were signs of component destruction in the past & some burning of the circuit board. I removed the two screws holding the board to the chassis & then looked at the board more closely. R1 5.6ohm 2W resistor then fell out of the board. So I checked it on a multimeter & re soldered it into the board. Some of the rectifier diodes had also been replaced & soldered to the original diodes legs, so I removed them & soldered them directly on the board. R4 &5 3.3ohm 1W were also burnt so I replaced these even though they measured ok. Suitable replacements for the 10D10 & V06B diodes are 1N4007 1000V 1A.
The above Image shows the PB-1076 Rectifier board. Check the board for any burnt components & problems that may have happened in the past. The electrolytic capacitor & large red resistor is a part of the DC to DC converter when using the Radio on 12 volts. The fuse holder seems to have been added & is inline with the 600v output from the rectifier for protection.
HIGH VOLTAGE CAPACITOR IN PA SECTION It has been suggested to replace C 13 ( 80pF 1kV ) Silver Mica which is the coupling capacitor between the 12BY7A driver & 6JS6C outputs, which can destroy the 6JS6C tubes. 80pF 1kV capacitors are very difficult to get, so I tried a 150pF & 220pF 500v Silver Mica capacitors in series, 89pF & it works fine. If you have problems with resistor R40 being burned out, then replace C 11 200pF 1kV Silver Mica capacitor as it could be shorted or intermittent. I used 2 x 390pF 500v Silver Mica in series. R40 is also a safety resistor & if you decide to use a standard white wirewound 5W type, then make sure you face the bottom of the radio away from you when turning it on or testing after replacing R40 just in case it explodes. C104 on the TX/RX relay may also need replacement & is the same value as C13. Warning, don't use ceramic types as they may not be temperature stable for the heat generated in the PA section.
ADDING OR REPLACING THE COOLING FAN Although the FT101B I originally started restoring had a Fan, I had recently purchased an FT101E that had no fan. These Radios get far too hot to use without a fan, especially when doing any of the TX alignment in the manual. The original Yaesu fans were 110volt & are not all that easy to find, & are very noisy. The footprint of the original Yaesu fan is less than a standard 80mm fan so it is not a direct bolt in to the chassis. I is a shame to have to drill into a Radio that is in very good original condition, but I decided that it was best to use a quality 80mm 12 volt fan so it would not be an issue in the future. The fan is bolted to the chassis with one 3mm bolt to hold it into place so that you can mark 3 other holes with a scriber to be drilled & tapped in the chassis. The fan will slightly mount off centre from an original Fan but it does not cause any problems.
I decided to use the ACC, accessory socket on the rear of the radio as it had one spare pin, ( pin 11 ) that could be used for the fans power. I ran a 15ohm 1/4 Watt resistor in line with the Radios +13.5volt supply along with a 100uF filter capacitor to filter the fans ripple. The 13.5 volts is also routed through the second set of switch contacts on the Heater switch. You have to cut to two yellow wires on the Heater switch & hardwire them together & heatshrinking for insulating. I used the +13.5 volt connection on the chassis socket Pin 19 of the PB 1183 IF Unit as it was close to the Heater switch.
ALIGNMENT First Thing to do before going any further with Alignment. Check what crystals have been fitted to the 10A to 10D positions. I have been caught out here trying to align a Radio that had been fitted with CB crystals. You will not be able to get the permeability tuned coils to track properly unless you use the correct crystals in the 10A to 10D bands. I found that the picture of the crystal positions in the FT101E manual were incorrect. Refer to the diagrams below for the correct positions. I have confirmed that my FT101E is as shown below with the WWV crystal under the 10D, & there is no position that is wired at all to the band switch for the Aux. It could be that Yaesu has wired some of these differently in the factory. Peter G4DJB has confirmed that for the FT101E he has, the Aux crystal is in the WWV position & the Aux is in the N/C position in the picture below. Please let me know if you find it different in your Radio.
The Crystal frequencies can be aligned by using a late model Radio tuned to the frequency of each crystal when aligning. Use the CW position & CW tuning meter to align the frequencies. This may not be able to be done as many of the crystals may not start reliably if you do this. The Fox Tango group suggests to align the crystals for the correct output level, not frequency. This means that when you change bands you will have to re calibrate the dial everytime. The trimmer capacitors TC16 to 25 may not correspond to the bands as shown in the picture on later FT101E models without the 11m Band.
Bad Ceramic Trimmer Capacitors have been found on many of the bands so I needed to replace them before going any further with the Restoration. I have since found suitable replacements from Malaysia which I now have available in stock. The Initial alignment of the Permeability tuned cores on the 10M band is very difficult. What you are doing is tuning the cores on 30MHz with the preselector at position 10, & the 10M trimmers on 28MHz with the preselector on position 9. This is to make the adjustments track over most of the 10M band. You will only get maximum power output & maximum receiver gain after repeaking the preselect that ends up being about midway between position 9 & 10. Its all a bit strange but it does give a better result than just peaking the whole thing at around 29MHz. The permeability cores should all be around the same height after you finish, don't go any further if they are all over the place else the lower bands won't track correctly. 80M TX adjustment could not move T105 so removed coil from chassis & loosened core with isopropyl alcohol. Still broke core so found a suitable core in PA stage L13 Cybernet chassis Radio. Could not get T102 / 103 to track TX with RX at 30MHz. At 28MHz seemed fine.
TRIMMER CAPACITOR REPLACEMENT The above picture shows the various trimmers for alignment & the colours indicate the capacitor values that are the same. TC1-4, TC11-25 ( Green 50pF ) Replacement is a TRIM 06 ( 5-55pF ) TC11 & 16 ( 80M Band ) are a larger diameter trimmer in the FT101E but the circuit diagram & parts list still indicates that they are 50pF but this could be incorrect. TC5 ( Yellow 10pF ) Replacement is a TRIM 04 ( 2-12pF ) TC6 ( White 100pF ) We have no replacement available TC7-9 ( Blue 40pF ) We have no replacement available TC10, 26, 28, 29 ( Red 420pF ) We have no replacement available Refer to the parts list at the bottom of this page to email us for prices.
TRAP COIL ALIGNMENT Many of these adjustments appear difficult & it may be better to not touch them. I was unable to hear some of these spurious signals on another receiver, & some appeared to be quite broadband noise spurious, not like narrow band tunable spurious. With the TC30 Adjustment trap, I could not hear any spurious on 28.160MHz as stated in the service manual. I recommend tuning a radio to 6.36MHz +/- & place it near L32 / TC30 & adjust for minimum signal on the receiver. This corresponded to maximum RF output on 28 to 30MHz.
CARRIER BALANCE Check the Carrier Balance by listening to the transmitter on both USB & LSB with a another Radio Receiver, & adjust VR1 & TC1 on the PB1184 board for minimum signal level on the Radio Receiver. You will have to compromise as the carrier will not be able to be completely nulled on both sidebands. Trying to do reduce the carrier output on a power meter as per the manual is past its used by date, & the alignment is not as accurate as listening to the carrier. SSB CARRIER POINT This adjustment has somehow not made it into the FT101B/E manuals. The adjustment is quite easy to do & makes quite a difference to the sound of the transmitted audio. I use a program called Sinegen on a Laptop computer to generate audio to do the alignment. Make sure that you have a clean audio signal if you use a computer & a transformer may be required to decouple any hum loops. Check the audio on another Radio Receiver before doing the alignment to make sure that computer audio is clean. Set the Radio to LSB & Input a 1kHz signal into the microphone using sinegen, & set the microphone level to read 60 Watts RF output power on a powermeter into a 50ohm dummy load. Then change the audio frequency to 300Hz & adjust TC3 ( LSB ) trimmer capacitor on the PB1184 board ( LSB ) for 15 Watts output. Then change to USB & set the microphone level for 60 Watts output with 1kHz audio input, & then change the audio frequency to 300Hz & adjust TC2 ( USB ) trimmer capacitor for 15 Watts output. Download Sinegen Software. Here ALC FAULT We had a problem with the ALC on our FL101 Transmitter. The meter barely moved & there was not much DC output from Diodes D1 & D2 in the ALC circuit. The Radio was producing up to 150 Watts PEP on the PEP meter so it was concluded that the Valves were ok. The service manual mentions a repair procedure& how to go about fault finding the circuit. They failed to mention that the 12BY7 driver could be a fault & not producing enough drive to the 6JS6C valves. We only found this by comparing readings with a good FT101B Radio. A multimeter was set to AC & connected to the junction of resistors R11 & R12 in the Grid bias circuit. When whistling into the microphone an output of around 3 volts peak could be seen on the meter. On the faulty FL101 there was only around 300mV maximum. We then concluded that there was not enough drive & that we should try replacing the 12BY7 dirver first & it fixed the problem. HETRODYNE CRYSTAL OSCILLATOR ALIGNMENT The Crystal frequencies can be aligned by using a late model Radio tuned to the frequency of each crystal when aligning. Use the CW position & CW tuning meter to align the frequencies. Using the suggested alignment in the manual will not get them on frequency which means that the VFO has to be calibrated everytime you change band. S METER ALIGNMENT The meter in these Radios are not all that accurate from S1 to S9+. There is only one adjustment VR2 on PB1183 IF board. I suggest setting the S9 reading for 50uV ( -73dBm ) input signal which is fairly standard. I calibrated the S Meter on 14.1MHz with 50uV into the antenna socket & tested it on each band. 1.85MHz S8, 3.60MHz S9, 7.10MHz S9, 14.1MHz S9, 21.1MHz S9, 28.1MHz, 29.1MHz S8 The Marker should read around S9 to S9 +10 on most bands. NOISE BLANKER
RECEIVER GAIN MODIFICATION This Modification may Transform your Old FT101 into a very nice sounding Radio. Have you ever thought that your FT101 had a bit of a Hot Receiver, with the S meter sitting quite high compared to other Radios. The symptoms of also AGC overload & generally high noise out of the speaker that masks weaker signals. I recently purchased a FR101 receiver that has similar circuitry to the FT101 radios. The receiver was absolutely horrible & everything sounded overloaded & distorted. Turning the RF gain back a bit did give some relief but it was still bad. Searching the WEB indicated complaints of bad AGC but no one had a cure. Tests here indicated that the receiver gain was far too high & that the AGC had a very poor dynamic range. Studying the circuits of the FT101 indicated that R22 has a few different values in the various models. The cure was to change R22 that connects to a 11 volt zener D12 on the PB1183 IF board. The resistor changes the gain of the receiver by changing the AGC voltage & a larger resistor will give more voltage swing of the AGC, so coping better with weak to strong signals. I fitted a 5kohm trimpot on flying leads in place of R22 so that I could experiment with it. Reducing the gain by increasing the value to around 3.9kohm & then resetting the S meter adjustment made the radio sound very nice. The S meter now moves much more, & the receiver is much quieter & weak signals can be easily heard. The gain on 10M band is still fine with this mod. Many other Radios have an IF gain adjustment which sets the S1 meter level by detuning one of the IF coils, but the FT101 series just seems to be tuned flat out. There are a number of modifications that others came up with over the years in the Fox Tango group newsletters. Unfortunately I did not have access to these until recently so I had to find my own solution. These may be better but I have not tried them. One is a simple zener diode mod in the AGC, another replacement of resistors around the RF amplifier, & another the addition of an O/P amplifier in the AGC circuit.
FREQUENCY ALIGNMENT We have heard many FT101's on air that are not on frequency. The trimpots that are used for alignment are not all that good & have far too much range, & the problem gets worse with dirty trimpots. It is suggested to replace the clarifier trimpot VR4 on the rear of the clarifier pot with a 1kohm multiturn trimpot, & also the zero set trimpot on the powersupply board with a 500ohm multiturn trimpot. To align the frequencies & clarifier correctly follow KB3JXW's web page link below. Adjust the 6 volt Voltage relgulator trimpot VR3 to exactly 6 volts before doing the alignment. FT101E W3JXQ FT101B Clarifier & TX/RX Frequency Alignment
BANDPASS FILTER ALIGNMENT If the Radio shows signs of power variation across the VFO dial then the filter may need alignment. The service manual procedure works quite ok & should be followed. The 6.36Mhz trap used for the 28MHz band can also cause problems if TC30 is not aligned correctly. Refer to the notes on Trap filter alignment above. TOUCHUP PAINT All paints were purchased at the local Hobby shop. For the front panel use Humbrol MATT 66 Dark Grey Touchup. For the Front Panel surround Tamiya AS-16 Light Grey USAF Spray Tin, or for Touchup Humbrol MATT 26 Light Grey. WANTED ITEMS None at this time.
REPLACEMENT PARTS Prices are in the parts catalogue pages below. Ordering & payment information is here. Ordering Ceramic Trimmer Capacitors Refer to above alignment section Mini-Kits Part Numbers TRIM04 2-12pF, TRIM05 2.5-23pF, TRIM06 5-55pF Yaesu Circuit Diagram numbers C13 80pF 1KV use ( 1x 150pF
& 1x 220pF 500v Silver Mica connected in series ) We
have a limited number of 82pF 1KV capacitors imported from the US available
( CAP/SM82 ) . See the Capacitor catalogue below for pricing. Mini-Kits Part Numbers CAP/SM82 82pF 500V Silver
Mica TPM500R 500ohm 25 Turn Trimpot
( suit replacement of Zero Set Adjustment trimpot powersupply board
VR4 ) Relay
Catalogue Download Section15
Includes Relays for Yaesu
FT102 IZ7DJR
Yaesu Mods
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