30-11-2012, 03:50 PM
Hi Paul, yes, the HRO Senior (the HRO Junior is rare over here, it was a stripped down version of the Senior) The Senior and the M, MX etc are for all intents and purposes the same, I think the MX has the Xtal within the phasing can, the Senior has a plug in Xtal on top of the phasing can and is much easier to clean should the need arise.
The next version time wise is the HRO 5 , the HRO 5t (t for table model) is aka the Reception set R106 MK11, electronically it's almost the same but it uses metal octal valves as opposed to the UX6 bases valves used in the Senior, MX, etc, the HRO 5t has a white "S" meter without illumination, the Senior has a yellow/orange meter which is illuminated, the white meter is scaled in m/a and the early meters are scaled in "S" units.
So far as I am aware the plug in coil packs are interchangable but if you obtain the coil packs seperately from another source they will need aligning to the receiver, the adjustments in the coil packs is by air spaced variable capacitors, all very easily accessable from the top of the chassis.
There are two types of coil pack (both interchangable) the General Coverage and the Bandspread, the bandspead coil packs cover the same as the general coverage but they have a bandspread option which is enabled by moving the contact screws on each coil pack can, the bandspread coil packs have two graph windows, the general coverage ones have one graph window and one logging window (white card) which you can jot down station details etc.
The bandspread coils go for more money than the general coverage ones, there are four bandspread coil packs for the full set, all other coil packs are general coverage, the bandspread coil packs are a joy to use when trying to resolve single signal reception and SSB on the amature bands.
The reduction drive on the HRO is well known and lives up to it's reputation, the anti backlash gears are cast not stamped out of thin brass etc.
There is a bit of a knack (easily learnt) when removing the tuning dial assy for cleaning/greasing etc the main thing to remember is that the outer surface of the main drive spindle bush (which is fixed) is eccentric to the main drive shaft, the inner dial (the one with the numbers on) slides on and rotates on the outer surface of the drive spindle bush and it has to be bang on otherwise the tuning mech. will start binding very badly, the basic trick is to rotate the tuning knob until the number "250" appears in the outer scale window, at that point the knob grubscrews can be removed and the whole assy, can be withdrawn, same for reassembly but on reassembley of the two halves of the tuning scale there is a pointer on the back which the gear teeth have to be aligned to, if all that is done ok then no problem, do it a couple of times and it gets quick to do. A word of caution with the HRO the output connector tags are both live when connected to a speaker matching transformer as is the B+ transmit relay link, also the pot shaft for the "S" meter set zero is live, if that pot is removed for what ever reason it must be replaced with it's chassis insulating washer otherwise shortie shortie. The B+ switch must be switched to off when changing the coil packs otherwise sparky sparky. I have a couple of HRO's in the Gallery. Early HRO's have round IF cans and are worth a bit, most HRO's you come across have square IF cans. Price wise you can pick a reasonable one up for servicing from around £70 to £120, probably a bit more if it has the bandspread coils, the coils seperately come up on Ebay quite often.
Lawrence.
The next version time wise is the HRO 5 , the HRO 5t (t for table model) is aka the Reception set R106 MK11, electronically it's almost the same but it uses metal octal valves as opposed to the UX6 bases valves used in the Senior, MX, etc, the HRO 5t has a white "S" meter without illumination, the Senior has a yellow/orange meter which is illuminated, the white meter is scaled in m/a and the early meters are scaled in "S" units.
So far as I am aware the plug in coil packs are interchangable but if you obtain the coil packs seperately from another source they will need aligning to the receiver, the adjustments in the coil packs is by air spaced variable capacitors, all very easily accessable from the top of the chassis.
There are two types of coil pack (both interchangable) the General Coverage and the Bandspread, the bandspead coil packs cover the same as the general coverage but they have a bandspread option which is enabled by moving the contact screws on each coil pack can, the bandspread coil packs have two graph windows, the general coverage ones have one graph window and one logging window (white card) which you can jot down station details etc.
The bandspread coils go for more money than the general coverage ones, there are four bandspread coil packs for the full set, all other coil packs are general coverage, the bandspread coil packs are a joy to use when trying to resolve single signal reception and SSB on the amature bands.
The reduction drive on the HRO is well known and lives up to it's reputation, the anti backlash gears are cast not stamped out of thin brass etc.
There is a bit of a knack (easily learnt) when removing the tuning dial assy for cleaning/greasing etc the main thing to remember is that the outer surface of the main drive spindle bush (which is fixed) is eccentric to the main drive shaft, the inner dial (the one with the numbers on) slides on and rotates on the outer surface of the drive spindle bush and it has to be bang on otherwise the tuning mech. will start binding very badly, the basic trick is to rotate the tuning knob until the number "250" appears in the outer scale window, at that point the knob grubscrews can be removed and the whole assy, can be withdrawn, same for reassembly but on reassembley of the two halves of the tuning scale there is a pointer on the back which the gear teeth have to be aligned to, if all that is done ok then no problem, do it a couple of times and it gets quick to do. A word of caution with the HRO the output connector tags are both live when connected to a speaker matching transformer as is the B+ transmit relay link, also the pot shaft for the "S" meter set zero is live, if that pot is removed for what ever reason it must be replaced with it's chassis insulating washer otherwise shortie shortie. The B+ switch must be switched to off when changing the coil packs otherwise sparky sparky. I have a couple of HRO's in the Gallery. Early HRO's have round IF cans and are worth a bit, most HRO's you come across have square IF cans. Price wise you can pick a reasonable one up for servicing from around £70 to £120, probably a bit more if it has the bandspread coils, the coils seperately come up on Ebay quite often.
Lawrence.
