Hello All,

The Philco T805 & NT808 arrived yesterday---tried to post last night, but internet connection soured just before...

Am at work this morning before clock-in, so not much time...

Both in nice shape cosmetically, just need some cleaning & detailing... The American-made T805 is a great performer---super sensitive with its tuned RF amp & audio has great, smooth bass sound ( all with only two easily removed "D" cells for power ! ), dial pointer is off about 50 kHz ( easy fix )... And it has an interesting "mechanical" feature I'll tell of later... Japanese-made NT808 had battery leakage and needs more "internal" attention...

Both were from same household---the seller got her NT808 as a high-school graduation gift in 1966, while the T805 was bought by her husband while he was in high-school in '62 or 3...

Pics & more later this week when I get time...

John

Got a couple pics tonight...

Forgot to mention that both radios are pretty hefty with cast "faceplates"... The American T805 has a really nice, genuine cowhide case in great shape ( including stitching )---also has an interesting anodized aluminum protective dial cover which slides from the right side ( wonder how many who have these are aware ot it ). The NT808, which looks like its made by Toshiba, has a vinyl case which is in good condition other than around battery opening...

Took the "dead" NT808 apart and was impressed by design---four easily accessed, external screws and the entire chassis comes out in one piece and is "self-supporting", also, the P-P output transistors are heat-sinked to chassis... Battery compartment has leakage residue & contacts corroded---applied 4.5 VDC directly to radio, but still completely dead with not even trace of audio... Tuning cap is mounted to chassis with three rubber "shock" mounts, and they are rotted causing it to "hang" against chassis ( see 2nd pic )... 1st pic shows radios as received along with a GE P-780 & Zenith Royal 500 to give an idea of their size...

More to follow as time allows... As always, hope to hear any comments and/or experiences with these radios...

Thanks... John

MOAR!

Moar closeups! More Info! Moar pics! - We want MOAR!

~ Mitch ~

Hey Mitch---looks like "moar ?" to come...

Noticed the first time I turned on the T805, the static between stations had that "hot" sound---those audio "artifacts" that you often hear on a very sensitive receiver...

Well, tonight I turned it on to listen to WSM 650 while working on the "dead" NT808 before dusk and station came in loud & clear which is unusual---so tried two other very sensitive TRF amp equipped sets that had batteries in them & received it also, but not nearly as clear and it was still somewhat in their "noise level"... Looks like this may be the "hottest" set yet in collection... Hope someone else with one will run across this thread & comment...

Spent considerable time cleaning battery leakage residue out of NT808. Plastic battery tube was riveted to chassis, but one rivet was corroded & it came off just before bulk of cleaning was complete---so gave it an extra good scrubbing... Also, cleaned residue off of part of chassis.

Applied power again to NT808 & did finally hear very faint "scruffing" as I turned it on & adjusted volume ctl. It's drawing about 10 to 15 mA of current. Tried audio signal tracer at volume pot---nothing... Guess I'll have to recap, though all the radios I've had of its vintage ( mid to late 60's ) have been fine with original parts... May do a little more in-depth troubleshooting for the "fun of it" before replacing electrolytics...

Looking forward to pulling T805 chassis & taking side-by-side pics of both sets "guts"...

John

Okay---just looked more closely at PCB and notice the molded plastic Toshiba electrolytics
which look much like the ones used in the early Channel Master sets which were prone to failure... Guess I'll head the re-cap "direction" first... Here is a closer view of PCB...

Has anyone else had these mid-60's molded caps fail ???

John

Not much time today for radios, but did turn on T805 mid-day out of curiousity and was amazed to hear WSM fairly clearly, so grabbed Sony TR-84 to compare---could just barely hear station in the noise level... This Philco is definitely the most sensitive AM only transistor set I've ever had ( or heard ) and still am amazed by its performance. Looking forward to doing some DX'ing once I get it cleaned up ! And on a minor point, noticed the knobs were solid metal & heavy---they sure put a lot into this little set...

Hope tomorrow to get more done on both...

John

Got both radios cleaned today & T805 back together as done---leather still really nice on this one & smells good... Need to order a couple caps for the NT-808.

Here are more pics---the flash sure made the scratches & imperfections look much worse than they actually are !

More pics---here is the "inside" of T805, its front with protective dial cover slid into place, and an "angle" shot... Note the "miracle" Ray-O-Vac "D" batteries I've had for around 37 years that still work great ( posted on these a long while back )...

And forgot to mention that dial pointer had simply slipped, causing the 50 kHz "offage"...

Will post progress on NT-808 when able...

John

Daaaaaaamm. Lookie at that awesome ferrite antenna!
John, can I come over and play?

~ Mitch ~

Hey Mitch---keep your eyes open ! Those radios don't appear to often, but the couple I've seen went for minimum bid under $10... This one was listed several months ago with min. of $8 but had no bidders---found old listing during internet search & contacted owner who offered both these sets as a "package" deal...

And notice the sub-mini IF cans & small PCB---they could have fit all that hardware into a smaller, plastic, horizontal coat-pocket set and had a real "sleeper" of a radio !

Sure hope one of the Philco experts will stop by and comment of this set ! Also, be great to find old ad(s) & other documents about it... With the clearly marked ( and labeled ) CD freqs. on dial, very hi-sensitivity, and powered by just two "D" "flashlight" cells, this would have been a great set to have in a fall-out shelter !

Order needed caps today for NT-808... Sure looking forward to gettin' it together !

John

Got caps the other day for NT-808... Tonight removed sticky, gummy residue from original tuning cap mounts & substituted six phenolic shoulder washers which fit chassis holes snugly---cap now securely mounted in proper position...

Removed PCB mounting hardware & P-P output transistors heatsink bracket ready for re-cap tomorrow...

Oh boy---this NT-808 has turned into a miserable headache !

Re-capped today & found two wires that were simply broken from their connection point---the antenna coil ground & one of the audio interstage transformer leads. And others broke during process... The wire strands were next to impossible to tin/solder since their plating was oxidized...

Caps were definitely bad---noticed one was cracked & audio did work afterwards, though it received only two strong local stations at low volume...

During tuning noticed loud "scratching" at low freqs. and found that something had scraped across edge of RF amp rotor section blades and left very small "flashings" of aluminum which shorted as they contacted stator---think this may have blown the RF amp transistor ( 2SA72 ) as it shorted its collector to ground in the process... Emitter voltage only reads -.1V where schematic says -.4V ( need to find SAMS schematic as the Beitmans is difficult to read )... It will be a real pain to remove PCB again with risk of more damaged wiring, but do want to get this radio going... Also, the RF & conv. transistors are shielded with ground lead & wonder if anyone has had trouble with that new of Japanese transistors developing whiskers... Put RF generator on it and IF passes its signal fine...

Did get the battery tube pop-riveted back onto chassis after major cleaning...

Looks like this will "drag on" awhile longer ! But have heard that this is a very good radio when working correctly, so plan to follow through... And it's definitely a good "looker"...



John

My estimation is that your P-780 should very much be on par with the T805. Hmm... I wonder what gives?

Hello Mescalero,

I have both a P-780A & H as well as a few other excellent performing TRF amp equipped sets & the T805 very noticeably outperforms them---am curious myself as to reason... Perhaps the RF amp transistor &/or stage has higher gain ? Would be great if another T805 owner would jump in with their experiences... Would really like to see the design specs on this radio !
It is also more sensitive to noise, but signal does win that battle... Still need to find some time to do some daytime DX...

John

Boy, this NT-808 is gettin' to me ! Spent most of today working on it with no result...

As mentioned earlier, thought that the RF amp transistor was degraded by tuning cap problem since only local stations were weakly ( low volume ) received and emitter voltage was only -.1 instead of -.4V---so removed chassis & loosened PCB to get access to leads, desoldered, and temporarily installed socket... Went through my transistor drawer and found two RCA 2N1632's which were a recommended sub & tried both with exactly the same results. Also, tried replacing convertor transistor w/no change in performance... Reinstalled the originals & got scope out and probed through the IF chain with each stage showing signal gain... Did notice when I'd power down & up, sometimes no reception until I touched circuit gnd. with test probe... Found that during that "dead" period, the collector voltage of 2nd IF amp transistor would fluctuate at a lower voltage, but went right to spec when reception returned... Oscillator operation seemed a little odd with amplitude varying much more than normal during tuning... Sure wish I had a working one of these to compare signals... Maybe need to look further into that "flaky" 2nd IF transistor... Any tips/ideas ???

BTW: Checked shield leads on original transistors & there was absolutely no "leakage"... Also, subs didn't have this lead & performed identically to originals...


Thanks...
John

Tune it to interfere with another radio and turn it on/off 'till it comes up playing "dead."
My guess is that the LO isn't coming up until you tap ground. If so, "dead" times will also allow other radio to play normally.
If other radio indicates that LO is still running and on frequency, suspect IF. Check with 455 KHz sig gen. to troubleshoot IF.
Edit -typos.

The T-805 had production runs using GE or Philco transistors. The ones with Philco transistors will out perform the others. Philco germanium transistors typically out performed other brands in small signal applications.

Would these have been the "bullet" cased surface barrier transistors?

Don, this T805 does use Philco transistors---were these transistors actually developed originally for the military ? Seems I've heard that awhile back...

Mescalero, it was just the 2nd IFT transistor collector voltage that fluctuated intermittently with power cycles that coincided with no reception---didn't happen at all today, so couldn't do any further checking...

Did spent a couple more hours today & replace 2nd IF transistor with NOS Toshiba sub I found it drawer---again, no change whatsoever in performance & emitter voltage -.6 instead of -.3V just as original... Very strange... So weird ! RF amp emitter voltage around 1/3 the schematic value & 2nd IF amp twice---even with new transistors ! Emitter resistors measure correctly... Voltages measured with both analog & digital meters ( & scope )...

John

What's AGC doing during this?