Estate Treasures: HP606A RF generator

Let's fire up a classic HP generator I picked up over the winter. We'll also check out a Leader LDC-823S frequency counter with sweet VFD display.
hparchive.com/Manuals/HP-606A-...
More info: www.hpmemoryproject.org/timel...

[@notimetolooz9655]

When you have the Leader set to period I think you can push the range buttons to select different time display. Over at the Antique Radios Forum someone started a thread about a HP606A that he just got. It is in the Test Equipment and Tools sub-forum, it started at the end of May 2022. Oiling the frequency range mechanism is a good idea.

[@harryshector]

This was current technology when I was an Air Force Precision Measurement Equipment Laboratory (PMEL) technician. These were my favorite signal generators, along with the HP 608. Marvelous equipment. I envy you.

[@waltschannel7465]

That is in great condition, both physical and cosmetic as well as operational! That calibrate knob is simple and creative.

[@SeekingTheLoveThatGodMeans7648]

Keep this up and you'll have more operating lab stuff than Mr. Carlson.

[@wb8vqv]

That thing is like vintage test equipment porn. What a beauty!

[@bluearcturus13]

The HP606A or B and the HP8640B are the very best and most precise RF Generators for radio and TV restoring. If you once have discovered the extreme accuracy of these, you will never use something different. Another very interesting and pleasant fact is, that these HP generators are built so well, that you can make distortion measurements through!!! these HP generators. Almost everyone tunes their radios to the highest peak levels, which is the normal way to do it. I do the same, but when I'm working on high grade radios, I also put a HP or Tektronix distorion analyzer to the output of the receiver and observe and adjust the to point with the lowest distortion near the peak of the highest signal output. Maybe you will go back to your Philco 90 and recalibrate it with this HP606. At first you probably will not notice much difference than before. But when you run the Philco 90 on very good outside antenna, you will be surprised how much of very weak stations are coming in, stations which weren't there before such a precision alignment. Easy way to calibrate the HP606: instead of using the headphones, put the scope in the headphone jack and calibrate the HP until you don't see any audio modulatioin. Much faster and even more accurate than only listening by ear. I can also reccomend to always put a good "dummy antenna" circuit between the output of the HP and the receiver you're working on. Best regards from Switzerland, bluearcturus

[@peteroneill404]

Recently I decided to get my 606A out of storage where its been for 20+ years. The controls were frozen but a clean and greasing of range and tuning gears it was good to go. While it did work some of the electrolytic caps had gone leaky and with them replaced it is good as new. These days no manufacturer would provide a tool to help you disassemble their equipment. By the way the output attenuator is almost identical to the HP 355D.

[@oldavguywholovesRCA]

I have one on my bench I restored. Love mine.

[@bobweiss8682]

You can get additional accuracy when using the crystal calibrator by looking at the audio using a scope rather than headphones. You can get a more exact zero beat visually than with headphones with limited bass response.

[@Joetechlincolns]

Yep, X Y mode utilizing Lissajous pattern.

[@EzeeLinux]

Commercial AM radio is most often modulated right up to 100% for negative peaks and you can run up to 125% positive peaks without audible distortion. Audio processing keeps everything within those limits nicely. Carrier cutoff only becomes an issue when a station is using C-QUAM AM stereo. The negative AM modulation is usually kept below 75% so that a synchronous detector will not lose lock on the PM left minus right stereo signal.

[@greggsvintageworkshop8974]

What a wonderful piece of vintage test equipment Bob! So pristine in both looks and functionality. The Leader Counter is fantastic as well. You are a lucky guy to be able to find, buy and use such quality vintage gear. Thanks for sharing!

[@theresters1]

I JUST CAN'T STAND TO LOOK AT ALL YOUR TOYS. I AM A WANNA BE TECH, NOT EVEN A HAM YET..73 YEARS OLD TO BOOT. I'VE ALWAYS TINKERED WITH CB'S KICKERS AND SHIT, LOVED SIDEBANDING, HAD A PEARCE SIMPSON SIMBA BACK IN 74 AND A TEMPO ONE, BUT LOST THEM AND MOST ALL MT CONGLAMORATION OF MOBILE CB BONEYAED JUNK. NOW, RETIRED, CLAMBORING BACK INTO THE SKIPPING FOLD BEFORE I GET TOO OLD TO TALK, LOL. MY WIFE REMEMBERS THE EARLY MORNING CH. 16/17 SB SHORT SKIPPING EVERYWHERE FROM NEW ORLEANS, LIL' ROCK ETC FROM MT QTH B'HAM AL. BAREFOOTING. JUST LOVE WATCHING YOU REPAIR THOSE OLD PORTHOLE SETS..AMAAZING. CARRY ON, GUY. I LOVE TO SEE A SELF TAUGHT PRO LIKE YOU! I AM ENVIOUS OF YOUR RECALL, MINE IS GOING AWAY RAPIDLY....SIGH...

[@hestheMaster]

Both are awesome pieces of vintage test equipment to have Bob. Blows away the stuff I have purchased in the past. Now that it is opened replace the grease on the innards of the bandswitch knob or you might break this one. I noticed a long Allen wrench for adjusting something in the sealed box, but what I am not sure. It is very cool HP piece of equipment.

[@bobweiss8682]

The long allen wrench is what you use to open the oscillator box. Particularly the screws along the side adjacent to the power supply/modulator. Getting the box off takes a good half hour or so.

[@vinragemania9312]

Bob the 606B was made for quite a while , i think its in the 1975 HP catalog (b version)

[@jdmccorful]

Nice instrument. Thanks for the look and your time.

[@cliffordjones8761]

The Manual recommends a 2 hour warmup time before using. There is a difference between Models A vs B. 2-7 Caution Damage to output attenuator may be incurred if: 1) Output is shorted in the 3-volt range, 2) External voltage is applied to the attenuator output. 2-8. The output attenuator contains resistors which can be burned out by careless usage. If the output is shorted out in the 3-volt range or if voltage is fed into the attenuator accidentally, these resistors may be burned out or heated up so that they are no longer calibrated. This may occur while measuring the sensitivity of the receiver in a mobile transmitter-receiver installation when the transmit button is pushed accidentally. An attenuator fuse is available as an accessory when it is desired to use this generator under conditions where the attenuator may be burned out (see paragraph 1-21). The resistors in the attenuator are NOT field replaceable. Do not open the attenuator to check these resistors as placement of the resistors is critical. The attenuator may be removed from the instrument and returned separately to the factory for repair. 00170-5 2- 2-15. B+ FUSE. 2-16. The regulated B+ voltage is fused on the front panel. If excessive modulation is accidentally applied to the instrument the tuned circuits may flash over from excessive peak rf voltage. This will blow the B+ fuse.' The instrument will have no output and the output level meter will be pinned to the left of zero. If this happens, the fuse must be replaced to restore operation.

[@rubusroo68]

nice bright vfd

[@bobweiss8682]

Most likely dried up grease on the bandswitch mechanism. Very common issue. Probably been going on for a while, breaking the original knob. The bandswitch knob on yours isn't original style. These are great instruments. Had one for many years, until eventually replaced it and it's VHF cousin (608), as well as a couple sweep generators with an HP 8662A.

[@bandersentv]

I'm jealous - the 8662 is an amazing generator. Ah-ha. You just solved a mystery. There was a knob tied to one of the carrying handles. It looks just like the bandswitch knob I see in photos of other 606As.

[@bobweiss8682]

Was wondering how long it would take you to figure out how to get it out of the case. :) The portable cabinet was optional with these things. If you look at the front panel, it has holes in it for 19" rack mounting. That's the reason for the internal AC power plug, as well.

[@bandersentv]

I seem to be accumulating a lot of rack equipment. Might be time to invest in a small rack for the workbench.

[@markseymour5558]

Hey there, pretty much caught up on bingeing your videos, did you ever tackle that Dumont Clifton? never seen a power supply that big! keep the great videos coming 👍

[@bandersentv]

Nope. Mainly because I didn't have a big enough workbench. Now I do, but have a pile of Predictas to restore first. I'll try to sneak it in sometime in the next year.

[@markseymour5558]

@@bandersentv Love those Predictas, , I can understand needing the space, look forward to it in the future, btw I think we were born in the wrong time 🤔, stay well

[@kermitmawyer1743]

Yes 1