Job
The IF section of a typical radios consists of two IF xfmrs and an RF amplifier tube. Many schematics give you the voltages at various points in the radio, so that would be a place to start. Also, you can use an ohmmeter to check for continuity on the primary and secondary sides of the xfmrs.
The IF frequency is too low to pick up on a regular radio (e.g., 455 kHz). Some of the inexpensive digital shortwave radios, e.g. my Degen 1103, can tune down to such IF frequencies. But, you might hear the IF freq, even with the second IF xfmr open.
Are you perhaps thinking of checking to see if the oscilator is running? That's pretty easy to do with a second radio. For example, with the antique radio on a station at 1000 kHz, tune the second radio to 1000 + IF (e.g., 1455 kHz). Rock the tuning back and forth on the antique radio and you should hear the oscillator squeal on the second radio. If you don't hear it, then the oscillator is probably not running. This checks the oscillator section, not the IF, which is what you asked about.
:There is a method of testing tube radios to determine if the IF section is working.....coupling two radios together.....Do anyone know a link where I can find information as to doing this task, or can someone give a discription aa to how it's done?
:Thank you
:
:Job
Why ???? Hans
Please look here:http://www.nostalgiaair.org/References/Articles/post/index.htm
Hans
::::There is a method of testing tube radios to determine if the IF section is working.....coupling two radios together.....Do anyone know a link where I can find information as to doing this task, or can someone give a discription aa to how it's done?
::::Thank you
::::
::::Job
:::
::Hello Job, this was a mistake. I am sory! Hans
:
:Please look here:http://www.nostalgiaair.org/References/Articles/post/index.htm
:
:Hans
:
:::::Thank you
:::::
:::::Job
::::
:::Hello Job, this was a mistake. I am sory! Hans
::
::Please look here:http://www.nostalgiaair.org/References/Articles/post/index.htm
::
::Hans
Hello Job, i be glad to help you! Hans ::
Yahoo.. for.. Hopalong Cassidy and Georgeous George "wrasslin" on the then 12 inch B&W "Big Screens".
Premium quality test equipment was big bux back in those days. Therefore I relegated the use of that chassis to decades of facilitated servicing in its use in the analyzing of other radios problems.
The unit was power transformer operated, so I had already averted the AC line isolation problem aspects. The minumal secondary problem would be a ground loop problem which could usually be avoided by the technique that I used in the transfer of signal levels between the two units. Considering that you can now locate yourself an appropriate AC power transformer design of chassis...or posssibly already have one to use. All you need now is a hand full of common RCA female phono jacks...use the small footprint
profile of units using the mini control ~3/8 in nut to mount to the chassis.
My first step was going to the IF stage with its IF input transformer and locate its first grid pin and as close to it as can be mounted on the chassis...mount one RCA plug with plug in, with its access being at the top of the chassis.
Use a large / high modeling clay dam on the chassis along with an adjunct STRONG magnet to catch any and ALL errant drill chasings whilst drilling that / further mount hole(s). An almost zero length wire jumper connects to the center of that jack to that IF "toobs" firstus gridamus.
Move over to the 6AV6-6SQ7's first grid and enact the same action again.
Then move to the first grid of the AF output tube and do same to that ..what it is..6V6..?etc.
The next aspect of the operation is the fabrication of the interconnecting test lead / Probe.
I knew that IF I used 1/4 in common phono lead like used on Geetar to amp cords or any of the RG family of coaxes, I would be enacting more capacitive loading and detuning that I would like to have had ...BUT...that is a given when a
lead is plugged into any of the added on /signal extraction/signal injection points specific jacks.BUT fortunately the sig level is of such amplitude that it is permissible, within tolerable degradation.
I optimized the lead line solution with the utilization of the longest AM car antenna lead that I could scrounge up. That ended up being about 4 feet so I was doing fine. If you "noobies" are not familiar with the innards of that cable, it is consisting of
a black vinyl overcovering and then a copper crosswoven shield below it which is surrounding a poly-vinyl tubing...does air conditioning water tubing or ice maker feed tubing come to mind... but not of such a great wall thickness aspect. BUT the whole
tubing is somewhat limited ion the tightness of radius that it can be bent into. Lastlt we have a small~28-30 ga enamelled copper wire that is just floating around in that massive inner wall space. It makes interconnects between the two connector ends.
The end result being the lowest loss and detuning effect produced by the introduction of this test line into circuitry.
The end of the cable that normally went to the Auto antenna was fitted with the male RCA plug and a micro sized radial .001 ufd @ 400 VDC Dcisolative cap was inside the connector in series from the jack to the coax inner connector wire mentioned.
The other cable end had its common AM "Rotamola" connector plug, so it was somewhat "probe" like in profile so its only mod was the soldering a short brass pin into its hollow end that also had that center wire inside. Final step... a la Tektronics
lab scopes of that day was the soldering of a short ..~3 in..length of black testicle prod wire to the top of the metal connector and terminated the end with a mini Mueller alligator clip. Duplicating the short grounding of the old 6006 probes of that time.
Needles to say I also had numerous other in /out connectors tied into that radio also, to intermittently robbing power supply
voltages,filament voltage, speaker VC connections, speaker output transformer connections for evaluatons/ tests.
Therewith, you have the crux of the info, with you being able to either take off or inject higher level RF IF AF signals between units for your trouble shooting.
73's de Edd
:but then I easily get lost..
Peter : I thought he was describing how he modified a discarded radio chassis to use as a poor man's testing devise. I thought it was a very innovative and interesting idea.
I figured it was something interesting but the more I read the more I got lost...
and I guess I just wasn't reading it slowly enough to follow properly.
marv
:sir Peter:
:More precise and exacting qualification of expression
:"huh" ......required.
:73's de edd
:Edd,
:You're a gas
:
:marv
:
::sir Peter:
::More precise and exacting qualification of expression
::"huh" ......required.
::73's de edd
:I guess all information is useful to someone and I do appreciation all comments regarding any information I'm looking for. However, being a novice at this if it is too technical I will become lost but this in no way takes away the importance of the information to myself or some other person with a similar problem. Hans link is very interesting and when I receive my signal generator I'm hoping to find out exactly where the problem is located with this radio.
:Thanks for all your comments guys.
:Job
:
:
:
:
::Edd,
::You're a gas
::
::marv
::
:::sir Peter:
:::More precise and exacting qualification of expression
:::"huh" ......required.
:::73's de edd