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FT101Z/ZD RESTORATION This WEB Site is Devoted to Maintaining Hybrid ( Transistor/Valve
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Friday 7th March 08 
| SAFETY IS FIRST Please read the Safety information before attempting any repair or restoration. 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. 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. Remove the covers & clean any dust from inside with a paintbrush & Vacuume Cleaner. Be very careful with front panels, pots, switches, knobs etc as there does no appear to be any spare parts available from Yaesu if you damage or break them. These things are becoming collectors items so it is best to try & keep it as close to original as possible. Factory modifications are fine as these fixed minor problems, but try not to change the operation of the Radio from original. Don't overdo restoration as over painting things doesn't look original or old. A large number of faults or intermittent's can be traced to dirt in pots & switches. 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. Check the VFO for tightness & any lumpy ness as this could be a sign that the VFO bearing need cleaning & lubricating. I have taken a number of Yaesu VFO apart & found the bearing holder with score marks in side. This causes the lumpiness & can be improved by cleaning & re greasing the bearing holder. It is best when reassembling the VFO to just finger tighten the front bearing adjustment until the VFO is very smooth& rotates easily. Use a tamper locking seal when you are happy with the adjustment to lock the nut so it won't come loose with use. I have found many Radios with this adjustment over tight. While you have the VFO out replace any of the light globes that maybe blown.
POWERSUPPLY It is best to replace the electrolytic capacitors on the PB-1968 RECT B board. Be careful & check that all voltages on this board have discharged before removing the screws in the board from the Radio.
The above Image shows the Power Supply RECT B Board. Notice the high voltage DC outputs along the bottom of the board. Keep fingers away from these as it bites. It is suggested that if you can find some stiff clear plastic thin enough to be cut with scissors then a cover can be cut out & bent to fit over the board. The Electrolytic capacitors should be replaced as they are commonly leaky or dry. CAPACITOR REPLACEMENTS 1 x 10uF 250V ( Use 10TKR450 ) 4 x 10uF 450V ( Use 10TKR450 ) 2 x 22uF 350V ( Use 22TKR350 ) , 1 x 33uF 250V ( Use 33TKR350 ), 1 x 47uF 250V ( Use 47TKR250 ). Refer to the bottom of this page for FT101Z/ZD capacitor Kits. If you have low HT when in TX mode always suspect either one or both of the main filter capacitors ( 200uF 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.
HIGH VOLTAGE CAPACITOR IN PA SECTION Replace the 1nF ( 0.001uF ) 4KV Black Block capacitor on the PB-1715 PA Board. These apparently go leaky or short & can destroy the Valves, although I think it could just be the brown glue that is used to glue them to the board. The brown glue is a common problem on older equipment that goes hard over time & becomes conductive. The capacitor needs to be at least 4KV rating & 6KV ones as shown in the picture are fine. Part number is CER1000/2
ALIGNMENT You will not find the information below easily anywhere on the WEB. The Picture shows the alignment trim caps for the FT101Z/ZD WARC version. Just follow the standard alignment for the non WARC version in the Service Manual, & do the WARC bands in the same order from the 10M band down to the 160M band.
The above Image shows the Warc version trimmers which are not mentioned in the standard Matinence Manual.
VFO REPAIR & LUBRICATION I have seen many tight & lumpy Yaesu VFO's. I think that it is because the front bearing nut was tightened too much in the factory, or the bearing holders are just worn out from use. It is best to remove the VFO from the Radio & at the very least grease the gears & adjust the front bearing nut. I usually undo the nut fully & check the grease inside & re grease. Then finger tighten the adjustment nut & then back off the nut by 1/2 a turn so it is not tight. Then check it by rotation the main tuning knob & if needed back off the adjustment nut a bit more. When you are happy apply some block lube sealant on the thread & nut so that it cannot undo. You might have to back off the nut even more if the VFO is still lumpy which will help prolong the life of the bearing holders. I have taken a number of these VFO assemblies apart, & the usual thing is scored bearing holders. The ball bearings usually look quite ok. If the VFO is very lumpy after greasing & adjusting the front bearing nut, then you might have to disassemble the VFO mechanics & try & smooth the scored bearing holders with fine sandpaper & then polish. I use a light grease ( Lager Fett ) or you can use standard bearing grease. For the shafts that pass through the mechanical chassis I use light machine oil. While you have the VFO out, check the operation of the two light globes & replace them if necessary. Suitable replacements are 12 Volt 60mA 4mm diameter globes part number Globe 3
PREMIX LOCAL UNIT ALIGNMENT The manual states to adjust the appropriate transformers for each band to a level of 300mV on a VTVM on pin 1 of MJ3. This should read Pin 3 of MJ3 which is the edge card connector of the Premix Local ( Xtal ) Unit. This adjustment pulls the crystals, & I have never seen the bands line up the same on the VFO dial. With a analogue frequency dial you have to set the VFO with the marker when changing bands. The digital dial reads correct frequency when changing bands, even if the crystals are slightly off frequency but may not line up with the analogue dial on some bands. Maybe the crystals were very accurately cut in the factory, & when adjusted to 300mV the frequencies were within a couple hundred hertz. Maybe crystal aging over time makes the frequencies different from when the Radio was new, & adjusting for 300mV will not get the frequencies accurate. I have not had time to look at a better way to align these so that the VFO is close on each band without having to re calibrate the dial. PREMIX UNIT ALIGNMENT My FT101Z had 27MHz fitted to the 12M band position & I wanted to remove it & restore it to original. After replacing the crystal & retuning the Premix Local Xtal for the 12M band I found that receive signals were low in level. The problem was traced to the Premix Unit & the band pass filter had been readjusted to suit the 27MHz band. I connected a DDS Sweep Generator Kit to the VFO input on the rear of the Radio, & set the sweep to 5.00 to 5.50MHz & the sweep rate to fast. I monitored the output on the J301 connector on the Premix Unit with a Spectrum Analyzer. You have to set the Spectrum Analyzer for the pass band as listed in table 7 in the manual so it was set to 33.5 to 34MHz. Adjustment of the T315 & T316 transformers peaked & flattened the response of the filter. I was not able to see anything on an oscilloscope but I think they forgot to mention in the manual that a suitable RF probe is required to demodulate the RF so that it can be seen on an oscilloscope. I then checked all other bands & found the 10M band was slightly out, so I adjusted the T317 & T318 transformers for that band. ALIGNMENT SSB CARRIER POINT This adjustment 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. Follow the instructions in the owner or service manual as it seems to work fine. Check the Carrier Balance after by listening to the transmitter on both USB & LSB on a another Radio Receiver, & adjust VR501 & TC502 as per the manuals. Trying to do the adjustment with a VTVM is past its used by date, & I doubt the alignment is as accurate as listening to the carrier. Download Sinegen Software. Here S METER ALIGNMENT The meter in these Radios are not all that accurate. I found that I was not able to get it close by using the alignment manual. I usually set the S meter trim pots ( VR403 for S3 ) & ( VR405 for +20dB/S9 ) to give a better curve. Set your RF signal generator for -53dBm for the +20dB/S9 setting & use a 40dB attenuator inline for -93dBm for the S3 setting. S 9 is usually a -73dBm signal but with a 20dB attenuator the +20dB/S9 reading was +5dB/S9 so not too bad. The Marker should read around +20dB/S9 on most bands. I use this procedure for most old Radios including the Kenwood's. ALC METER ALIGNMENT I have never been able to get the ALC meter to read very much even with the mike control flat out. I think the correct setting for ALC on the front panel is just until the ALC meter starts to move no more. The transmitter was however putting out in excess of 120 Watts on the lower bands so was overdriven. With excessive audio input I only ever saw the ALC meter on two radios reach around half the ALC scale but the transmitted audio was terrible. I am still not sure if other FT101Z/ZD's have the same characteristics or if its particular to my radios. There is no adjustment for the ALC reading on the meter, only the 0 reading with the VR401 trim pot. RF PROCESSOR With the Processor turned on it may be normal for the P-P output power to be slightly lower even though the average talk power appears to increase. I have noticed this on two Radios & suspected that there may be a fault in the processor circuitry. I was never able to find anything & it may just be normal on the FT101Z/ZD. There has been mention that transistors in the older Radios can loose gain, or Xtal Filters can go off in this area, & cause Processor problems. There is a transformer on the IF Unit T404 that is peaked with the Processor turned on. Use the Sinegen software as the audio source into the Radio. I found when driving the Radio with a 1kHz tone & setting the mik gain for 100 W P-P output, when switching on the Processor the power dropped to 60 Watts P-P. With voice I found little difference in P-P output power. FREQUENCY DRIFT This can be a problem on transmitt & when going back to receive the frequency is correct again. I had a problem in this area & found that when I pushed in the TX clarifier switch the problem was fixed. I first replaced the trim pot VR1801 on the clarifier PC board but this did not fix the fault. I decided to remove the clarifier board & replace the resistors on either side of the trim pot along with capacitors. It also seemed a good idea to remove the cover over the small relay & clean the contacts. I have had no frequency drift problems after doing this. It may be a good idea to replace the trim pot with a multiturn type as the adjustment is very critical with a standard trim pot TOUCHUP PAINT I spent some time in the Model Hobby shop matching up paint the same as Yaesu uses on the FT902, FT101Z/ZD Radios. The colors below are very close & should only be used to fill chips. Don't go too far doing everything as its best to keep as near original as possible. These colors are the numbers we found in Australia & may not necessarily be the same in other countries. Front Panel ( Dark Grey
Matt finish) Humbrol Matt 66 WANTED ITEMS None at this time. REPLACEMENT PARTS Please email me for prices on the Parts listed below Relay Catalogue Download
Section15
Includes Relays for Yaesu FT102 FT101Z/ZD Capacitor Kit
$22.50 plus post PA0PGA's
FT-101ZD-Survival Guide (Rev.3).pdf (21MB)
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