#175

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Long project with 11 parts up to now - and now: Bad final transistor!
Part 1: • #153 Drake TR7 Part 1(13)
Part 2: • #154 Drake TR7 Part 2(13)
Part 3: • #155 Drake TR7 Part 3(13)
Part 4: • #156 Drake TR7 Part 4(13)
Part 5: • #157 Drake TR7 Part 5(13)
Part 6: • #158 Drake TR7 Part 6(13)
Part 7: • #159 Drake TR7 Part 7(13)
Part 8: • #160 Drake TR7 Part 8(13)
Part 9: • # 161 Drake TR7 Part 9...
Part 10: • #162 Drake TR7 Part 10...
Part 11: • #163 Drake TR7 Part 11...
Part 12: • #175 Drake TR7 Part 12...
Part 13: • #178 Drake TR7 Part 13...

Опубликовано:

16 окт 2024

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Комментарии : 16

@davidv1289 Год назад

What a shame! On the bright side, you and this transceiver have provided thousands of us with an invaluable learning experience. Thank you, Stefan. Hopefully the owner will decide to once again save this vintage equipment from the landfill. Regards, David

@dl7majstefan753 Год назад

The owner gave me a "Go" to repair the final

@Homer19521 Год назад

Bummer. Had the PA go out on my IC-7700 SII twice! Very expensive repair. Apparently the 7700 did not like my QTH. Never had that issue with more than 20 other rigs thru the shack. I sold it after the 2nd repair. 👍

@PapasDino Год назад

Another great tidbit of tribal knowledge for TR7 owners! TNX Stefan! 73 - Dino KLØS

@sylweksliwka7986 Год назад

Chciałbym mieć takiego sąsiada .😊

@zdzisiek1979 Год назад

Bardzo fajny sprzęt i ciekawa relacja z naprawy :)

@berndb.5097 Год назад

That's life in electronics.🤷‍♂ Even transistors and power transistors in particular have a life limit. At some point the bonding wires gave up the connection to the chip. In the case of power transistors, the cold and warm phases accelerate aging and thus the loosening of this bonding connection. The TR7 is definitely worth repairing. I would not use him as a well-repaired spare parts supplier. But let's wait and see how the owner decides. 73 Bernd

@dl7majstefan753 Год назад

Maybe i´ll try to open the transistor and examine it with a microscope

@andytomm1 Год назад

Is it possible that the transistor had a "weak" base connection since manufacture, or the driver is actually over-driving it due to low ALC action? or something else of course.

@dl7majstefan753 Год назад

Tnx, but the ALC is set acc. to the manual and active

@DAVIDGREGORYKERR Год назад

There must be non inductively wound Wire Wound resistors that could take the heat and not burn out.

@dl7majstefan753 Год назад

Right! And these small resistors are metal film types.

@ulrichhensel8171 Год назад

😃👍

@jmbt7548 Год назад

Gute Darstellung des sehr interessanten Fehlerbildes. Ich finde allerdings, dass viel zu wenig Messungen vorgenommen werden. Auch ein Austausch des Transistors und dann Oszillografieren des Schwingungsbildes wäre nicht sehr aufwändig, aber sehr hilfreich gewesen. Ihr Englisch ist sehr gut zu verstehen, obwohl Sie kein Muttersprachler zu sein scheinen, eher scheint Deutsch Ihre Muttersprache zu sein. Nichts für ungut.Vielleicht ist diese Rückmeldung ein wenig hilfreich ;).

@dl7majstefan753 Год назад

Bin Deutscher, Englisch u.a. im Beruf erlernt. Die Finals werden getauscht - sind nach Absprache mit dem Eigentümer (er bezahlt) schon bestellt.

@andytomm1 Год назад

Stefan, gw8ljj has a matched pair at lower cost on the very well known sales window.