#204

[@dennisqwertyuiop]

always look forward to see you on Sat. mornings,,thanks Peter,your the best

[@TRXLab]

Thanks Dennis very much appreciated!

[@stopnwonow5044]

Beauty transceiver in hands of a great technician. Congratulations Peter, and thanks for sharing you knowledges.

[@TheRadioShop]

Thanks for sharing Peter. Those test points are really hard to get at. You had to work for that one! 73

[@bblod4896]

Engineers were drinking too much sake when they designed the alignment procedure for that radio.

[@TRXLab]

Yes it is very annoying to get down to the test point. Thanks for stepping in my friend! 73

[@111111111Tiger]

excellent job, I'm sure the owner was a happy camper

[@hectorpascal]

Nice job Peter, but what interests me most is WHY those circuits were so far off tune. What is the physical process that makes such large differences appear over time? Is it the result of temperature cycling and bad design?

[@stargazer7644]

Components age and change value over time. Mechanical vibration and temp swings can cause small shifts in adjustment points. Caps dry out and suffer chemical changes in their electrolyte. Materials used in construction change their electrical properties over time.

[@adrianchadd]

Hi! So I have one of these that badly needed the crystal oscillator realigned. It turns out that there's a 433.03MHz test point you can use without having to pull the board out - I traced the circuit enough and found the resistor/wire coming out of the shielded section with L7 also is 433.03MHz. It's not the right point for the level check, but it's definitely enough to determine if the oscillator is on/off frequency. I compared the signal level at the test point seen before and after calibration and saw it at the same level so I figure I'm no worse than before. And now the output is within a few Hz of 433.03MHz and now the radio is basically dead on frequency. Thanks for this video! It helped me get over my fear of opening my IC-1271A up and now it's properly on the air!

[@injoelsgarage3934]

Peter, thank you for sharing. That thing was a real son of a gun, holey socks man! I wonder if they could have put more shields in that radio? I call that electronic surgery. You absolutely amaze me most of the time Peter. Once again thank you very much. Joel

[@TRXLab]

LOL no I really guess more shielding is hardly possible :^) Thanks for watching

[@80Loke]

Ive learnd very mutch from your videos, thx :) 73

[@TRXLab]

Really glad to hear that! Thanks 73

[@andylaurie326]

just a quick shout out to you for these remarkable videos. I've been following your channel for awhile now and am always amazed at your knowledge and expertise.

[@TRXLab]

Thank you Andy very much appreciated!

[@TKomoski]

Thanks for sharing and see you next time Peter. *Cheers* *_73_*

[@TRXLab]

Thanks for watching Tom 73

[@SuperMeganw]

very good video takes good job from Gary in the UK.

[@berndb.5097]

I still remember my activities at 23cm. If you did not have the right measuring equipment here you were stuck. You are really well stocked. At that time I always worked with transverters and just had to hit the LO frequency exactly. On the input side I had to adjust an exact 28MHz signal. That was no problem with my measuring equipment. The transverter was under the roof 2m below my antenna. I hardly had any coax losses. I really like your Racal Dana frequency counter. I should get that one too. Maybe I'm lucky and find one on ebay or a flea market. 73 Bernd

[@TRXLab]

Hi Bernd, yes you really need to have a lot of different devices to get the jobs done.. Additional to keep all those devices in spec and calibrated to have them reliable...The Racal counter is really a nice device but be careful buying it on ebay. The early models had very much issues with the front buttons. Many folks had to swap out all buttons as they simply quit working! 73

[@berndb.5097]

@@TRXLab Thanks for the tip, Peter.

[@bobkozlarekwa2sqq59]

You make it look so easy! Great job!

[@TRXLab]

Yeah it may look more easy as one think...Thanks for comment

[@prezillogic9230]

I love all your videos please make more I like to learn from you

[@9h1gb]

Hi Nice work. I too have one of these rigs and mine has a couple of issues too. I was wondering if you happen to have a soft copy of the Service manual as the copy I have does not have the alignment section on it Thank you for any help

[@fredshead7114]

You must have a headache after that one, what a job to do...must have a lot of patience Peter from Fred in Uk g4vvq.

[@TRXLab]

Yes right for radios like this you need patience as it really takes time to move forward....73

[@hansbertram5435]

Dear Trx- Bench, I bought this Transceiver for 200€, but the Transmitter has no out- put power and I have no idea, what the reason is, driver or endstage😂 I have only a spectrum analyzer dsa 850 from Rigol and changed the endstage, but no good result.😢

[@michaelm1keyhardy865]

Brilliant but im not technically minded but very intrested to watch you work the problem out.

[@TRXLab]

Thank you glad that you liked it

[@waynethompson8416]

Wow!!! What an education you just gave me! I had always thought that the frequency display on a transceiver showed the "exact" frequency because it was a form of Frequency Counter. Now I know better. Since it isn't measuring the exact frequency, what is it displaying? Is it just counting turns of the dial or something? I guess unless you have a way to put a frequency counter in line with the SO239 going to the antenna, you can't actually know what frequency you are transmitting on. Does the lack of accuracy of the display also apply to the receive frequency?

[@stargazer7644]

On a few older radios, the display was a frequency counter. But in PLL radios, the display is something the cpu puts up to correspond to the settings it is sending to the dividers in the PLL circuit to result in the desired frequency. But for this to be accurate, all of the local oscillators have to be on frequency. Think of it like the speedometer in your car. It simply measures the revolutions of the tires, but unless the tires are the right size and properly inflated, it won’t be accurate. The same PLL circuits are used to set frequency for both receive and transmit, so yes it affects both. Even a frequency counter is only accurate if its timebase is adjusted to the right frequency.

[@happymark1805]

the SMDU is only 1050MHz max not 1296MHz so the power measurement could be not correct.

[@berndb.5097]

Hey, this is a Rohde & Schwarz device. This company writes often less on the nameplates than the device itself can afford. I think the measurement of the power was accurate enough ;-)

[@happymark1805]

I have a bird but when I go outside the freq range I get wrong measurements and this is more than 25% higher than its build for

[@berndb.5097]

@@happymark1805 Compare it. Do you see any differences between the SMDU Z1 and your BIRD wattmeter? The used RF rectifier diode determines the cutoff frequency of your measuring device. If you put the appropriate "slug" in your BIRD it would work too. In the SMDUU Z1 a corresponding component is installed. There is definitely a small measurement error. Rhode & Schwarz therefore guarantees only 1050 MHz to be in their specified tolerances. I'm not worried about that. The measurement error is certainly well below 5%.

[@happymark1805]

every measurement outside the specs is deemed not correct, that goes for every instrument especialy if you are 25% over the max freq intended so there is no way to tell if it is off by 10%(full scale) or even more, since it measures 9Watt it could be 10Watt if the correct meter was used, use the equiptment for its intended purpose or you get measurements that are worthless.

[@berndb.5097]

@@happymark1805 Maybe Peter should not have done the video. Because he does not have the right device to measure power at 1296 MHz. Maybe he should have cut out the part with the power measurement. Then nobody would have been upset about that ;-) ;-)

[@thom3124]

" No user serviceable parts inside." Icom's are always a pain to work on. I wonder also if this is one of those radios that has the operating system on VOLATILE ram.

[@TRXLab]

LOL yeah no user serviceable parts inside....There is a new RAM board installed but I did not look deeper into that.

[@bblod4896]

Seems this radio was designed not to be aligned. Do you think each module was aligned on a jig then the radio was assembled? Thanks for the video.

[@TRXLab]

Yes most likely on a jig as as it can't be aligned during production..

[@OleF112]

Nice video, Peter. I hate this kind of radios, because you have to invest so much time just to to a 2 minute jobby at some small areas. I often find my self thinking " Hm, may i cut the shielding like a thuna can, and solder it back in place after...;-)" What i did was to drill holes beside the nozzle of a vacuum to get to the aligment points, and solders it with new plates. That was a special gov-radio , and i was i a critical hurry... So anyway, i guess the OM was very happy with your work. So am I! 73 de Olaf

[@TRXLab]

Yeah that is the point too much time only for preparing a single step of alignment. I was thinking about the idea drilling a hole but I was a bit concerned about drill cuttings. 73

[@rohnkd4hct260]

Good radio. I have the IC-271 (2M).

[@RadioamateurKjellSvendsen]

After been off air for abt 20 years I then just now found my IC751 having a 100 of bad issues, and hell, I really do wish I'd had the skill to fix it, but no - No go. So sad

[@educatedmanholecoverbyrich8890]

Peter: Is this radio a little deaf?

[@michael_pa4mic]

I like the speed the videos are coming, watching now an nice welcome this morning with an cup coffee. Thanks Peter. Ps. What kind of cable you use, they are nice flexible?!

[@ethanpoole3443]

Typically your foam (as opposed to solid) dialectic coax with stranded copper center conductor will be quite flexible. By comparison, solid dielectric and/or solid center conductor will be quite stiff and rigid.

[@80Loke]

I think hes using ecoflex on that yellow cable

[@TRXLab]

Thanks Michael! The coax was bought as high flexible lab cable but it is a long time ago and I don't know what the type is. It is Belden but can't remember the type...

[@michael_pa4mic]

@@TRXLabOk, is it triaxial cable? thx in advance

[@chrisj0]

Hey Peter, I have a question; why did you used two different frequency counters towards the end for the alignment procedure? As always, I really enjoyed the video. Thanks!

[@TRXLab]

Hi Chris, that is a kind of convenient as I can observe the transmitter frequency while I'm aligning one of the oscillators... Thanks for watching

[@repairfreak]

Nice job again 🙂👍

[@TomaszBorowskiTOM124q]

what's about SSB, I had an issue, FM was perfect but SSB gave a harsh modulation.

[@TRXLab]

Valid question but as I said I did not show the whole process as we already have a video online where we go through all single steps. SSB is tested fine.

[@dennisbauer3315]

Sorry TRX Bench, thought I may catch you here on another matter, do you think you could look into the 49:1 transformer, please, I am confident of any suggestions you could make or show, if you had the time. Other wise ignore, understood, thank you. Dennis, VK4JDJ

[@TRXLab]

Time is short to do all I want...

[@coblecam]

Wow! I would have given up! 73!

[@MicheIIePucca]

I love how you say "Z" like us Canadians (ie: zed) :)

[@TRXLab]

oh really did not recognized that ...Thanks

[@MrSuperheterodyne]

And in UK too. 👍

[@Daveyk021]

Considering the frequency, 1.xx GHz, was it worth all that for 5KHz? They user can just the dial a little to optimize reception or be on frequency? P.S. - You have a great voice and accent. I used to work for Krautkramer Branson, back in the day, and I miss the accent in our meetings and the three training visits I had to Cologne, Germany.

[@TRXLab]

5 khz is far too much for SSB operation. only 30Hz can be heard and more than 200Hz and you won't find your sked partner on the band...

[@lyntonprescott3412]

It was easier to get into an enigma machine lol 73

[@chrisj0]

lol, is that joke still funny if the video's author is German? ;-)

[@lyntonprescott3412]

Well Peter liked the comment!

[@TRXLab]

Guys to be honest I do't even know what you are talking about??

[@lyntonprescott3412]

Peter try a You tube search for The Enigma machine and I am sure you will know the device used for coding messages. Lynton.

[@gigicraioveanu1309]

Hi Peter I saw you are doing very good job in fixing Icoms, I need also a repair job for mine, can I ask you for your help?Thank you. 73 Gigi YO7NE

[@organiccold]

That radio looks new inside. 73 From M0IVC - CT9ABQ

[@TRXLab]

yes still a nice radio 73

[@alancordwell9759]

Very nice job Peter, you are a brave man!!

[@TRXLab]

Thank you Alan!

[@ojjenkins7110]

All mode??? Wo ist AM??? :-) Well SSB is really a vastly over modulated carrier without one sideband haha. I wonder how the factory had the allignments set up as they went down the assembly line? Danke sehr Peter.

[@TRXLab]

LOL yeah AM is stolen haha. I believe they did the alignment on a jig and send it then to the assembly line. Thanks for comment OJ!

[@ojjenkins7110]

@@TRXLab You bet Peter, love your videos. I had Obershule Deutsch and have forgotten a lot :-) That was back in 1966 to 68 :-)

[@MAURICIOFALCAOPY5MZ]

Fantastic Job Peter!! Congratulations from Brazil . 73 PY5MM

[@TRXLab]

Hi Mauricio, glad to see you and thanks for watching 73

[@zinkzoyd]

Nice job peter, Good counters those old racal dana's, I have the 1991 model

[@TRXLab]

Thanks Buik! Yes Racal Dana was a good company so sad that they quit...

[@zinkzoyd]

English company peter that made laboratory test gear and equipment for the ministry of defence far as i know,@@TRXLab

[@KJ7XJ]

Another enjoyable video Peter! Thanks!

[@TRXLab]

Thank you Eric!

[@mrbambix]

oh dear what a nightmare Peter, great video though !

[@w.rustylane5650]

I cannot understand why anyone wants to communicate on such a high frequency. The radio waves go what, 500 feet? Just not my cup of tea. Way too much shielding for those high frequencies. I don't even make contacts on 70 centimeters. 2 meters is about as high as I go. There's just too much power lost in the higher frequencies. I even use 213 coax on my 2 meter radio. Cheers & 73 from W Rusty Lane K9POW in eastern Tennessee

[@pietroplastina2786]

You must of invested a lot of money in your test equipment. Is it worthwhile financially to keep it up or repair your equipment you get. Is it even worthwhile to put it on you tube. Sorry I dont want to be nosy. Even so I am not into TRANSMITTERS and receivers. Good luck. And best wishes. GOD BLESS. You must have a lot of passion in this field like I do in my electronics field.

[@TRXLab]

you do what you love

[@robertcalkjr.8325]

Thanks Peter!

[@TRXLab]

Always good to see you Robert! Thank you

[@FlexxVision]

U like Icom service nightmare ? Good think needs time ^^

[@TRXLab]

I would be bored without ICOM. Thanks for stepping in

[@psionl0]

WOW What a horrid design. It must cost more to align this set than to recondition any other set. ;)

[@TRXLab]

Yeah that is true to much labour...