Amateur Radio Station DL7MAJ, Munich / Germany I´m a retired engineer and from time to time i´ll show here some topics regarding repair/restauration or basics in the field of electronics, amateur radio, measurement equipment and so on. It´s just a hobby for me - i don´t earn money with it and i have no commercial interests (no clickbaiting). So simply have fun watching my videos - or not.... it´s up to you! PLEASE NOTE 1: High voltages may be lethal! Do any work on electrical equipment only if you are trained and experienced! PLEASE NOTE 2: My time for personal advice or repair support is limited; i don´t have much time for it. This is no commercial repair shop, maybe i can help you from time to time, but it´s up to me whether i accept any jobs or not! I try to read all e-Mails and comments and try to give a short answer if possible, but please don't be offended if I don't reply or if i refuse to give any support.
Hi Stefan. Pardon me for saying you look a little tired after this fix. Thing is, this is the true satisfaction of using you educated skills to repair a broken instrument. Take a break now, collect your wit, and forget about the battle for awhile. Cheers from West USA.
Manmanman Stefan, da hat man Dir aber wirklich ein faules Ei ins Nest gelegt ! Ich bewundere Deine Ausdauer, manch einer hätte das Gerät schon längst über den Jordan geworfen und wär zum nächsten Funkhändler gefahren, um sich was schickes neues zu kaufen. Die Herausforderung, das Ding zum Laufen zu bringen zeichnet Dich aber als wahren Funkamateur aus. Eigentlich hätte man das Gerät einem angehenden Funkamateur in die Hand drücken müssen, um sich im Technikverständnis zu beweisen. Es gibt kaum ein besseres Anschauungsobjekt wie diesen faulty TXRX der zeigt, was für HF- Fallstricke einen überraschen können. Drück Dir die Daumen, dass der FT221 Reparaturbericht im einstelligen Bereich bleibt (obwohl es ja immer spannend ist, Dir bei der Arbeit zuzuschauen 😉) 73, bleib gesund von DL1LAJ Andreas
What an unusual problem, transformer failure is way down my list of suspects. Guess you got lucky (???) I have not seen that glue used on transformer windings but have seen plenty of damaged components and PCBs. Hopefully the alignment resolves all PLL issues - looking forward to part 9 and beyond 😀. Regards, David
that corrosive glue killed more transceivers than operator error. The solvent dries out, becomes porous, absorbs moisture, and eats away the insulations, even the legs of the components. It's a well known problem in Yaesu and Kenwood transceivers made in the 70-es and 80-es.
Great to see inside. I wonder how much knowledge the authorised batrery changers have and how much care they take in the procedure? In the uk at least its relatively recent that land use was licenced for such devices. Reading the opinions of prospective users or even rescue personnel is somewhat revealing. Ignorance is a remarkable thing. Why do replacmet batteries cost almost as much as a new device ? Even sealed bolt on batteries that are user changable. I think i'd rather have one of these that i had check myself than not have one at all for want of not being able to afford one. It is also legal to use unlike keying up on an aircraft frequency to get help in a remote catastrophe, or whatever other solution you can think of. Also I'm not going to accept some nonsense of.. if you can't afford £10/£100/£1000 per month for the subscription you shouldn't be doing it. Sarsat is global and open for any register user. It saves rescue teams hours or days and is surely the most accessible and efficient distress system going for remote and inaccessible areas. Why is the cost of safety so high? If you need to say because accidents cost more you clearly don't get the premise of a PLB. Every year we are battered with news reports of lost(missing) hikers in Scotland. Deliberate generation of a public hate for people "having to be rescued that shouldn't be there" What a difference it would make if these were accepted as commonplace here. It reads as though responsibility is not permitted here. The government and your peers don't allow it. You couldn't be responsible for not activating the life at risk device at any other time, and you certainly couldn't be responsible for changing the battery in such a thing. A great video. Informative. Interesting. Contentious!
Hello Stefan, I se you have a HP counter is it a 5340A, i have a 5340A working so if you need to service your sometime you know where another is, if you need any measured values.
you can use an MC1350 to amplify that signal, in case of absolute necessity. It has the advantage that its gain can be set with an external resistor, and the IC is really cheap.
Hallo Stefan, den LM703 habe ich damals nach dem Vorschlag von DL4CS nachgebaut. Aber sicher hast Du seinen Vorschlag schon beim Googeln gefunden. 73 Bernd
A very funny movie to watch, but not so funny to live! I checked my bench stock, but no 703s to be found. You might look at the TI THS4130 or THS4131 as a substitute (with a small adapter board), around $8 US from Mouser or at your favorite supplier. Regards, David
Hoe about putting a proper transformer with diodebridge stabilizer transistor and big elco's and throw that switching source in the bin instead of servicing it
I noticed it only had 2 pins on the power plug in the 1st video and wasnt impressed, Ive never seen that before, I think I would change that. Very good thorough analysis. I have to say in my experience those old Philips caps in the smaller sizes are generally bad but you are quite right its getting harder to get axial replacements.
Many Philips Equipments have only two pins; the case is therefore isolated and not grounded! That´s made intentionally to avoid ground loops but requires some considerations in the measurement arrangement. Isolation of the scope is good enough (safety class II, double insulated)
@@dl7majstefan753 Ive not seen that in New Zealand, perhaps local regulations forced this to be changed before import. I'm not sure how a scope can be double insulated if the metal case can become live?
@@campbellmorrison8540 The metal case is painted and there are ground connections on the front, which have to be grounded before use! The double isolation is referred to the primary wiring and transformer isolation. That´s all i know.
Manmanman, nimmt ja kein Ende mit dem FT221, Stefan. Man könnte meinen, FT steht für Fehlerteufel ;-) Zum Glück sind die Bauteile nicht noch mit irgendwelchen Klebern befestigt, der sie irgendwann mal durch Zersetzen angreift. 73, beste Gesundheit von Andreas, DL1LAJ
Tnx Andreas, ja, zum Glück gibt es hier diese Kleber nicht! Die Elkos scheinen auch nur gelötet, nicht geklebt - hab aber noch nicht alle visuell inspiziert. Drück mir die Daumen....hi.
I wonder if over time with the output set so high that the diode was stressed providing the ALC and that's why it failed, although that theory is a stretch. OR it was just the diode's time to go! ;-) Look forward to Part 7, have a great weekend Stefan! 73 - Dino KLØS
I don´t think, that the diode was killed by high output. Even with high output, the ALC-voltage is not more than some volts - just sufficient to control two depletion type FETs in the SSB-chain. The most endangered diode ist the germanium diode just behind the capacitive divider from the output; could be killed by transisnts during RX/TX switching. But this diode is OK!
Hey Stefan, I see that the saga continues. It's amazing how many little things you can find wrong with a rig like that. Looking forward to your next video. Stay healthy my friend.
It's crazy how many errors accumulate over time. In addition to all the age-related errors in the components, there are also those of the golden screwdriver heroes and "ingenious" modifiers ;-) But you exposes them all.👍 It was very interesting to watch your work. mny tnx es 73 de Bernd
Nice Rig Stefan, when i was getting my ham license early 80´s the Yeasu FT-101ZD was introduced LED frequency was very cool back then. Bye the way all mail i tried to send you bunced back after a week non deliverable. 🙃
Thankyou very much Stefan. I see you went through much pain to achieve the final result. I know this pain working on older test equipment. I am once again a FT221R owner (for fun on 2m like old days...). Thankyou for sharing your hard won efforts. Excellent video's...73 de M0BTZ
Amazing repair , heck what a problem last scope picture spot on timing , good work, I also work on a TS-450S it had the leaking audio CAP problem but i have another thing maybe i dont know but if i listen to USB mode on 20M on a staton and then switch over to LSB i hear the same station loud and clear, so it demodulate SSB in both sidebands ? I dont think this radio has ISB, i have not tested TX yet saw some comment on TX on both sidebands caused by leakage erode on PCB need to get a MIC int was not supplied. 👍
@@dl7majstefan753 Ok so the switching is done inside the front panel i will check , i just notised that the IF-shift is not workin either in SSB mode only CW mode that can explain it is in the AM selection, IF-shift is off in AM and FM mode.
Surprising that the inductor adjustment is not covered in the alignment procedure as it affects the PLL operation significantly. Looking forward to the transmitter alignment. Thank you for sharing your knowledge with us Stefan! Regards, David
You've worked very hard on this one, Stefan! Look forward to seeing the TX tests and alignment. I've learned so much from watching your channel! Thank you!
Sir, someone is selling the Japanese version ic 750a which is an untouched never been used New Old Stock as they say. How many years do you think it will still last? And in your honest opinion, do you think I should buy it? Thank you so much.
these video s can be s survival of humanity if an atomic war breaks out. those could be the few devices that can survive an EMP. those new ones since 1985 with integrated circuits and varicaps can not certainy not those with inthegrated circuits based on mosfets of nowdays
@@dl7majstefan753 the ones who have them will pop up right after day zero my oldest is an FT901 from yeasu kept in mint conditions, it is a hybrid he only ic is for frequency display
Very nice sir. You don't need another camera. You do very nicely with what you have. Good clear video and audio. Thank you for your time to make these videos.
