HRO-500: Kickin' my Arse!

[N8ETQ]

   Damn thing is in "Lock" 500kc low. It's not
the dial.  Damn!  What a "Freak Show", Makes an
R-1051 look "Logical"?  Perfect follow up to Ed's
excellent post.... It's only "Stupid" below 4mcy,
bands 1 and 2. There is a 26 mcy xtal osc kicked
in for those.. And of course it works FB...

73

/Dan

[KA3EKH]

Although I have never worked on one just looking at it says it all, over complicated, primitive transistors and must have a mysterious method of generating signals that cannot be anything like a modern synthesizer. May almost be as bad as one of those Wadley Loop pigs, I have always thought the Racal 6217 was one of the worst to work on and least understandable receivers ever built but that’s because I have had the misfortune to work with a couple. I have not had the opportunity to open a HRO-500 yet. I think of all the old first generation solid state super receivers the WJ stuff is still my favorite. But keep the faith, after all any man who can replace and realign the chain on a 1051 can repair a HRO.

RF

[KM1H]

IF you replace all 24 electrolytics, out of tolerance resistors, leaky germanium transistors and then follow the manual alignment it is easy
If it is an original 75 series you have a lot more work ahead of you

Carl

[KA3EKH]

Where do you get germanium transistors these days? Wonder if the ones you buy on EBay NOS are just as leaky? I remember years ago having to maintain sync generators that use buckets of those stupid PNP germanium transistors in the divider circuits and the leakage of the transistor would also control the bias of that circuit so modern transistors were useless as replacement. Then there were the ones that were used as switches in power inverters that without the leakage would not osculate. Don’t know what this has to do with the HRO; probably just want to waste time writing about the alleged Good old days.
 

[Pete, WA2CWA]

NTE Electronics still lists a number of germanium PNP transistors as replacements for most the devices in the HRO-500. They also list the vendors and quantities available.

[Jeff W9GY]

Had an HRO-500 once, had to replace all the electrolytics before I could get it to behave.  However I was never impressed with the S/N or strong signal performance of this receiver.  OK if you like collecting vintage stuff, but I never thought it was much of a performer.  (just my 2 cts.)

[KM1H]

The MDS is well below any antenna noise, even on 10M, so the SNR is more than sufficient if its in good repair and alignment. It is a very quiet low internal noise radio with no phase noise of the modern synthesized sets. Listening on a quiet almost dead 10M and hooked to a 4el yagi at 100' it clear copies signals that the TS-950SD barely knows are there and the hot rodded HRO-60 is in between.

As is the R-388,51J4 and other commercial/military sets they werent designed for big antennas and they do overload but at least it has the step attenuator which is more than the others have.  Plus the RF gain control doesnt defeat the AGC. For a 1961 design it was better than some of its competition including the 51S1.

Ive found NTE quality to be all over the map and many HRO-500 replacements dead out of the envelope. Ive managed to keep ahead of needs most of the time and even going for European and Japanese subs when I can find them.

Carl

[N8ETQ]

 Yo'

    I agree, and thanks for the "Input". Yup,
nothing to write home about. It's been a PIA
to this point. It has no endearing qualities
that would make it desirable. The R-1051 on
the other hand at least has ISB and impeccable
stability. The R-1051 uses a similar "Spectrum
Generator" scheme for the PLL. Give me a "Pulse
Swallowing Divider" and a MC4044 phase detector
any day!  I'm not sure the owner is all that
"In To It". This thing has a 26 MC xtal osc
up-converting the 0 - 4 MC bands to the upper
4 bands of the RX. Since the top band 29.5 to
30 mc won't lock, that also makes 3.5 to 4mc
dead. Amazingly that 26mc osc is NOT phase
locked.

   Right now the thing works pretty gud from
4 to 28.5 MC and by tweaking L19 I can get
"Acceptable" performance out of the BC band.

  Carl, What does this mean? How can I tell?

  "If it is an original 75 series you have a lot more work ahead of you"

   Thanks guy's. I'll keep Y'all in the "Loop".

73

/Dan

[Pete, WA2CWA]

  Carl, What does this mean? How can I tell?

  "If it is an original 75 series you have a lot more work ahead of you"

   Thanks guy's. I'll keep Y'all in the "Loop".

73

/Dan

Look at the back of the receiver; lower left on the chassis, there should be a number stamped there. The first two or three digits tell you the series. The "75 Series" was the earliest of the receivers. The HRO-500 Series: 75, 88, 102, 122, and 140. Servicing this receiver can be a head scratch-er the first time around.

[N8ETQ]

Thanks Pete,

    Whew, It says 88.

/Dan

  Carl, What does this mean? How can I tell?

  "If it is an original 75 series you have a lot more work ahead of you"

   Thanks guy's. I'll keep Y'all in the "Loop".

73

/Dan

Look at the back of the receiver; lower left on the chassis, there should be a number stamped there. The first two or three digits tell you the series. The "75 Series" was the earliest of the receivers. The HRO-500 Series: 75, 88, 102, 122, and 140. Servicing this receiver can be a head scratch-er the first time around.