20-11-2012, 07:42 PM
Hi Paul, yes take your time and do a good job it will be worth it, main mechanical problems usuallly end up with the tuning reduction box, they are prone to backlash if it's had a hard life, appart from the usuall checks in the reduction drive there is not a lot you can do normally, if yours is ok it's still worth doing some routine maintainance on it, clean, regrease/oil, check/adjust endfloat on the appropriate shafts, make sure the anti backlash gears are offset correctly etc.
Them bathtubs do leak, replace/restuff as is your wish. Check the resistors on the bias board etc.
The S meter looks like a non original add on, this is common, the S meter circuit on these receivers isn't the best but it should function as an indicator.
As you are probably aware it employs an Xtal filter so if you feel the need to re align the receiver bear that in mind as you will have to determine the exact Xtal frequency with a sig gen then align the IF's to that frequency, there has always been a bit of a debate on the IF alignment involving Xtal filters, Ideally a sweep and display is required but you can use the standard sig gen and meter method and get very good results as it is only a single Xtal design, remember that the phasing control is not an adjustable front panel operated feature so that setting it as a preset will be quite critical, you will probably be aware that the Xtal filter at its narrowest setting is for single single reception on CW. If when all is done the single signal reception does not stand out then remember that you need safe crackers fingers to get the tuning bang on the nose, it's very criticall, if no joy then first would be to strip the Xtal holder clean and dry the Xtal and re assemble, if that fails it is possible that the Xtal for whatever reason is totally inactive or there is not enough coupling (check associated capacitors etc) or over damped.
Yes there is a mod for improving SSB reception using the BFO, the most common and simplest is to increase the BFO injection voltage by making up a short length of twisted wire capacitor for the coupling and adjusting to suit, that's what I have on mine.
You are lucky as it still has the topside RF screening can, quite often they are missing as is the one underneath that screens the tuning gang capacitor.
OK, going to upset you now, I have a NOS in original packaging perspex window for mine (not fitted yet) NOS ones are hard to find but good seconhand ones do turn up at auction etc from time to time, but there will be competition, same goes for an original manual, having said that one went on Ebay the other night for under £15 an HRO one from the same seller went for around £25, neither really prohibitive, it depends on your take on these matters.
Not sure about the socket on the rear apron, Diversity/RIS maybe? you would need to draw a basic circuit diagram showning its relationship with the rest of the circuit.
Them drilled holes on the front panel:
They can be filled and made to disappear no problem, the problem will be getting a paint/texture match.
I would be inclined to fit those slightly curved (outwards) black blanking grommets until you really decide which way you want to go, screwing up a front panel refurb will look bad whichever way you look at it.
If I remember right, turning the noise limiter full on does reduce and distort the signal, the criticall point is just before the distortion occurs, you need some repeated fast risetime interferance ideally to hear the limiter working, I have something down our way that ticks regular like a clock, the noise limiter will cope with that no problem and should do with spark/ignition type interference. I can't remember off hand what type of noise limiter is used in the AR88 without consulting the book of words, my Hallicrafters SX28 uses a Lamb limiter which works spot on.
Have fun and don't drop it on yer toes...
Lawrence.
Them bathtubs do leak, replace/restuff as is your wish. Check the resistors on the bias board etc.
The S meter looks like a non original add on, this is common, the S meter circuit on these receivers isn't the best but it should function as an indicator.
As you are probably aware it employs an Xtal filter so if you feel the need to re align the receiver bear that in mind as you will have to determine the exact Xtal frequency with a sig gen then align the IF's to that frequency, there has always been a bit of a debate on the IF alignment involving Xtal filters, Ideally a sweep and display is required but you can use the standard sig gen and meter method and get very good results as it is only a single Xtal design, remember that the phasing control is not an adjustable front panel operated feature so that setting it as a preset will be quite critical, you will probably be aware that the Xtal filter at its narrowest setting is for single single reception on CW. If when all is done the single signal reception does not stand out then remember that you need safe crackers fingers to get the tuning bang on the nose, it's very criticall, if no joy then first would be to strip the Xtal holder clean and dry the Xtal and re assemble, if that fails it is possible that the Xtal for whatever reason is totally inactive or there is not enough coupling (check associated capacitors etc) or over damped.
Yes there is a mod for improving SSB reception using the BFO, the most common and simplest is to increase the BFO injection voltage by making up a short length of twisted wire capacitor for the coupling and adjusting to suit, that's what I have on mine.
You are lucky as it still has the topside RF screening can, quite often they are missing as is the one underneath that screens the tuning gang capacitor.
OK, going to upset you now, I have a NOS in original packaging perspex window for mine (not fitted yet) NOS ones are hard to find but good seconhand ones do turn up at auction etc from time to time, but there will be competition, same goes for an original manual, having said that one went on Ebay the other night for under £15 an HRO one from the same seller went for around £25, neither really prohibitive, it depends on your take on these matters.
Not sure about the socket on the rear apron, Diversity/RIS maybe? you would need to draw a basic circuit diagram showning its relationship with the rest of the circuit.
Them drilled holes on the front panel:
They can be filled and made to disappear no problem, the problem will be getting a paint/texture match.
I would be inclined to fit those slightly curved (outwards) black blanking grommets until you really decide which way you want to go, screwing up a front panel refurb will look bad whichever way you look at it.
If I remember right, turning the noise limiter full on does reduce and distort the signal, the criticall point is just before the distortion occurs, you need some repeated fast risetime interferance ideally to hear the limiter working, I have something down our way that ticks regular like a clock, the noise limiter will cope with that no problem and should do with spark/ignition type interference. I can't remember off hand what type of noise limiter is used in the AR88 without consulting the book of words, my Hallicrafters SX28 uses a Lamb limiter which works spot on.
Have fun and don't drop it on yer toes...
Lawrence.
