General Category > Amateur Radio
Project 775
BoomboxDX:
I read somewhere -- probably one of the ham forums -- that the 701 has some issues that have to be fixed when bought used. Some part that's hard to obtain, or one has to come up with a workaround. I don't recall what it was...
Josh:
I've never heard of any common issue with the 701, the 720A however has a few that must be remedied before they take place, or hard to find parts will be needed.
Seems an internal rotary relay (used to switch front ends) has far too much tension on a spring and causes the part to beat itself to death, reducing the tension eliminates the problem.
I can remember crap like this I heard decades ago, but not what I had for lunch yesterday.
:D
Josh:
Breaking Quarantine
I found someone local to bead blast and powder coat the 775s poor cabinetry. At first I tried to find my goto place where I'd had a Romanian AK74 blasted and powder coated several years ago but couldn't remember where it was, mebbe they gone under. But fb, as much as I dislike anything zuckerberg, revealed a proprietor with a home blasting/coating shop, called and made arrangements for said blasting/coating.
Ran into a snag as the inside of one cabinet half has a large sheet of what I assume is sound deadening material of a synthetic felt nature, glued firmly over a substantial area of said cabinet. It also had a clothe-like sound passing baffle over the speaker port. Both of these would be ruined by the heat of powder coating, or misapplication of the bead blasting process.
So it was decided to simply glass bead the exterior of the cabinetry, the insides of wich are coated in a type of bluing or similar that is conductive, where powder coating is usually a insulator. In consideration of the above, spray bombs were the only recourse.
So while the cabinetry was undergoing the bead blasting, I vetured forth to Lowes only a few miles away and found they were indeed doing business during thapocalypse. Got some dark grey texture finish rustoleums and went back to the bead blasters.
Blasting took off all exterior coating and greatly reduced the apparent scratches and all traces of rust and corrosion! Inside, the cloth materials were unhurt.
Took all home and set up operations in the porch to keep dust and pollen off the surfaces post and ante spraybombing runs. Cleaned the surfaces to be painted with alcohol to remove any oils or other crap.
Holy crap this stuff is vile smelling. Spraying a few light coats, varying the pass direction and angle of attack made for a nice uniform coat, and the longer it dried the better it looked. I didn't like it at first when it was still wet, but now think it looks great, something Inuoue-san might be proud of.
Anyway, it looks like something the factory would have done, can't wait to put it together with the less blemished front panel and see how it looks.
73's and best regardses!
pedafo:
Just found this interesting forum / discussion group and as I was wondering how to fill the option filter slots for the 9mHz and 455kHz slots as well.
As I would like to "improve" my Tx/Rx audio on SSB having the 3.3khz wide SSB filter FL-257 availabe at my desk I wonder if it would be worthy to go ahead with the FL-96 stock filter replacement for the 455khz IF and try to replace de FL-80 with the FL-70 or FL-103 on the 9mhz IF.
Would one expect the FL-257 be efective for better audio intelegibility on RX and TX (when installed on the FL-96 slot) even for dx? or for dx it would be better install the FL-44A instead pairing it with the stock filter FL-80? :-\
I read a 775DSP thread on eham stating a "neat mod for the IF board that opens up the restricted transmit audio a bit. This is done by replacing the soldered-in stock FL-80 and FL-96 filters (2.4 and 2.8 kHz, respectively) with the FL-103 and FL-257 (2.8 and 3.3 kHz, respectively)".
Also someone shugested "On the reciever end of it i took out the FL-222 1.8 455khz SLOT and replace it with the FL-257 3.3khz" but this suggest that it would be only on RX side thus not improving TX side.
Will thank you in advance any thoughts you may share.
73 pedro
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