Forums :: Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives
Support This Site: Contributors :: Advertise


It is currently Nov Thu 14, 2019 2:14 am


All times are UTC [ DST ]





Post New Topic Post Reply  [ 24 posts ]  Go to page 1, 2  Next
Author Message
 Post subject: Received 1st Zenith Royal 500H---needs work( fixed ! )
PostPosted: Dec Sat 11, 2010 5:25 am 
Member

Joined: Oct Mon 26, 2009 10:02 pm
Posts: 6177
Location: Indianapolis, IN
Hello All,

***Editing for restoration of pics to post ( 2-3-2012 )***

Received 1st Zenith Royal 500H today---chassis 8HT40Z2...
It sure needs work---has the infamous bad/worn volume control which gives no or full volume, audio loud but distorted, and cosmetic issues... Label at top looks good except for air pockets between ( laminations ? ) at ends... Even with poor audio, tuning is smooth & easy with what seems like the good sensitivity & selectivity these radios are known for. From what I've found online, these volume controls are not available---so considering "tacking" in an internal trimpot to preset a decent audio level which can be easily removed later...

As always, like to hear from anyone who has had any experience with these radios...

John


Attachments:
500H 5.jpg
500H 5.jpg [ 90.09 KiB | Viewed 5241 times ]
500H 1.jpg
500H 1.jpg [ 139.58 KiB | Viewed 5241 times ]


Last edited by xrhonda91 on Feb Sat 04, 2012 2:51 am, edited 4 times in total.
Top
 Profile  
 
 Post subject:
PostPosted: Dec Sun 12, 2010 3:25 am 
Member

Joined: Oct Mon 26, 2009 10:02 pm
Posts: 6177
Location: Indianapolis, IN
Disassembled today & did more cleaning... Brass plated inset around speaker grilled appeared permanently stained and didn't want to damage plating with polish like I've seen on others, so spent tedious hours scrubbing with Q-tips---first with water for water soluble "dirt", then with 91% isopropyl alcohol for smokers residue, then over & over with windex. Turned out pretty good but will probably go over it again before quitting... Same basic thing with speaker grille, but less dirt to contend with and used toothbrush with windex to get holes clean.

Surprised to find that transistors are still socketed in these & volume control held on by nut and easily removed for "repair" attempt---see that shaft end is exposed on back side and am thinking of finding high-quality mini-pot to somehow couple to it...

Anyone know of source for replacements for these volume controls ? Or have successfully repaired or modified another to work ?

Thanks.
John


Top
 Profile  
 
 Post subject:
PostPosted: Dec Sun 12, 2010 1:03 pm 
Member
User avatar

Joined: Feb Fri 27, 2009 11:43 am
Posts: 1014
Location: Tucson Az
Hi John, I like the color of your set. If you do as good of a job on spiffing it up as your RCA Globetrotter it should be a good looking radio. Do you know if the volume pots are the same as earlier 500 models. I have a spare chassis. I'm not sure what 500, I think B. Here is a picture of my 500 collection
Image
Good luck with your new project. I'll try to figure out what chassis I have and if the volume pots are interchangeable.

_________________
Rob


Top
 Profile  
 
 Post subject:
PostPosted: Dec Mon 13, 2010 4:04 am 
Member

Joined: Oct Mon 26, 2009 10:02 pm
Posts: 6177
Location: Indianapolis, IN
Nice collection Rob and thanks for offer---the shaft on 500H control appears to be around 1/16" diameter while the earlier 500's were around 1/8". Checked this on one of my 500E's which has a bad speaker ( which I'd also like to repair )...

The on/off volume assembly on this is amazing---bend locking tabs from mounting "frame" outward and whole assembly comes apart ! Too bad they didn't use a better resistive element in it... If they were available, you could actually replace that section separately. Did gently clean element & wiper and ohmeter showed smooth resistance change, but still failed in circuit...

Got cleaning complete ( unbelievable how much "residue" had penetrated into brass plated inset ! )... Used another small pile of Q-tips including dry ones at end to "buff" out finish...

Also, got re-cap completed---but absolutely no difference in audio... Even after "tacking" in a good 5K pot, sound was loud & distorted---could clean it up a bit by flexing lower right corner of PCB slightly. Guess I'll have to pull it apart again...

I have the original owner's manual for 500E which I've scanned---would you like a copy of this, also ? Also, service data for all up to 500h.

How does your 500H sound ? Have heard many say that audio quality is excellent, but what would you compare yours too ?

Thanks for response & pics... Below is pic of mine after cleaning:

John


Attachments:
500h5++.jpg
500h5++.jpg [ 85.98 KiB | Viewed 5241 times ]


Last edited by xrhonda91 on Feb Sat 04, 2012 2:25 am, edited 2 times in total.
Top
 Profile  
 
 Post subject:
PostPosted: Dec Mon 13, 2010 4:29 am 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 1532
Location: Oakhurst, California 93644
Wow John! What an improvement over the first picture ... it's amazing what a little soap/water and elbow grease does to a dirty/stained radio. 8)


Top
 Profile  
 
 Post subject:
PostPosted: Dec Mon 13, 2010 6:16 am 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 1539
Location: Manitowoc, WI USA
I have a similar one that has the peeling/bubbling top gold trim issue. Someone used to make a replacement for that. Is it still avaliable?

IIRC, mine is odd in that it takes a couple of seconds to "warm up" before it will play. Certainly is a hot performing radio.

And, I just might have a volume control for that model...

_________________
We improve things by making them worse...


Top
 Profile  
 
 Post subject:
PostPosted: Dec Mon 13, 2010 7:25 am 
Member

Joined: Jan Mon 04, 2010 2:52 am
Posts: 3179
That looks like a dandy radio, inside & out. No, there are no new volume control replacements available on the market for these pocket transistor radios. You just about have to salvage one out of the junk bin.

As far as the volume rheostat, a little spray of isopropyl alcohol could have been useful. If this proved to be unsatisfactory, a minute spray of Radio Shack 64-4315 could have been used (although the oily residue from this tuner cleaner may temporarily detune the radio in the process).

As far as the audio, I would definitely start out by replacing at least the electrolytics.


Top
 Profile  
 
 Post subject:
PostPosted: Dec Mon 13, 2010 7:41 am 
Member

Joined: Jan Mon 04, 2010 2:52 am
Posts: 3179
http://cgi.ebay.com/Zenith-Royal-500H-T ... 45f76604c7

There is a Zenith Royal 500H transistor radio on eBay right now that is being sold for parts. You might be able to salvage a volume control out of this.


Top
 Profile  
 
 Post subject:
PostPosted: Dec Tue 14, 2010 3:12 am 
Member

Joined: Oct Mon 26, 2009 10:02 pm
Posts: 6177
Location: Indianapolis, IN
Thanks Atwater10---like your avatar !

HadYour Phil---Yes, I found that reproduction label online http://www.radiolaguy.com/info/Zenith_R ... _plate.htm , but it costs nearly what I paid for radio. The surface of my label is excellent, just has "air-pockets" at ends---tried to carefully "vent" these using a sharp pin on backside, but while inserting it through backside became fearful I'd go all the way through ( might try again later )... Do you know if label will come off of radio without being damaged ? Could release air-pockets, flatten with warm-iron over cotton cloth, and reattach with double-sided tape... Funny you mention that "warm-up"---my RCA 9-TX-2 does same thing. Did you put much larger value caps in DC input circuit ?

Volume control checks good after cleaning with smooth operation from both ends using ohmeter and I "tacked" in a good 5K pot from junkbox and audio behavior similar---think I might have a crack in PCB or bad connection causing ground fault... Also can flex lower-right corner of PCB slightly and audio quality improves noticeable, although volume issue not affected...

Blustar1---did replace all electrolytic caps and carefully cleaned volume control ( see paragraph above )... Will probably "attack" problem again this week or weekend... Saw that "parts" 500H on Ebay & have it on "watch" list---will probably sell for more than mine when auction ends...

Thanks for responses...
John


Top
 Profile  
 
 Post subject:
PostPosted: Dec Tue 14, 2010 4:26 am 
Member

Joined: Jan Mon 04, 2010 2:52 am
Posts: 3179
Being that the audio is still poor, I would check the coupling capacitors as well. If one of those should be out of tolerance, it could very well be giving you the condition that you were describing.

If the problem should still persist, I would start checking the transistors too with a good curve tracer (beginning at the audio output stage).


Top
 Profile  
 
 Post subject:
PostPosted: Dec Tue 14, 2010 6:34 am 
Member

Joined: Jan Mon 04, 2010 2:52 am
Posts: 3179
I would certainly give a higher priority as to obtaining another similar volume control though. Even if this means purchasing another for parts, a working radio is preferable to two non-working radios any day.


Top
 Profile  
 
 Post subject:
PostPosted: Dec Wed 15, 2010 2:44 am 
Member

Joined: Oct Mon 26, 2009 10:02 pm
Posts: 6177
Location: Indianapolis, IN
Hello Blustar,

The cap which couples audio to driver from detector stage ( via volume control ), is an electrolytic and was replaced with new part.
Sampled audio at this point with my signal tracer and it seemed clean.

There is a PCB connection problem somewhere in audio stage, but will have to disassemble radio when I have more time to troubleshoot... Definitely plan to get radio working if possible... Think volume control may actually be okay after cleaning since radio failed in similar manner with a known good pot and control checked okay with multimeter... Don't have a curve-tracer, but do have transistors to sub if necessary---easy to do since they are socketed...

Will probably get back to project later this week or weekend...

Thanks.
John


Top
 Profile  
 
 Post subject:
PostPosted: Dec Wed 15, 2010 6:38 am 
Member

Joined: Jan Mon 04, 2010 2:52 am
Posts: 3179
If one of the leads from that electrolytic should extend over the board top side as it connects to the volume control wiper, I would steer it away from an inductive source (such as a transformer in particular) as it could cause the radio to detune.

Watch also for possible shorts between the foils along with cold or broken soldered connections. Keep us informed. Thanks.


Top
 Profile  
 
 Post subject:
PostPosted: Dec Sun 19, 2010 3:23 am 
Member

Joined: Oct Mon 26, 2009 10:02 pm
Posts: 6177
Location: Indianapolis, IN
Got faults repaired today---radio complete & works great !

Turned out that upper right corner ( component side ) of PCB had a small chip which opened up the ground connections to the volume control and 1st IF transistor causing near maximum volume and strange reception issues---easily repaired by jumper...

Also, PCB pad where .22 uF capacitor lead attaches to output transformer pin had broken loose from trace, probably from stress---this caused distorted audio. Looped a small component lead clipping around collector pin of transistor socket, layed it along surface of PCB trace, then looped around transformer pin and soldered...

After repair, volume control works perfect---shot a little FaderLube in it for good measure... Also, flexed PCB before reassembly to ensure all was good...

Radio now works great---very sensistive & selective and good audio... Vernier operation of tuning dial is excellent... Listening to the Grand Ole Opry with it right now...

Sure like to hear from anyone this info might help !

Thanks.
John


Attachments:
500H PCB fix paint2.JPG
500H PCB fix paint2.JPG [ 84.67 KiB | Viewed 5241 times ]


Last edited by xrhonda91 on Feb Sat 04, 2012 2:32 am, edited 1 time in total.
Top
 Profile  
 
 Post subject:
PostPosted: Dec Sun 19, 2010 6:31 am 
Member

Joined: Jan Mon 04, 2010 2:52 am
Posts: 3179
Wonderful John! I'm really glad that you got that transistor radio working. I couldn't help but to suspect that the trouble with your radio centered around the volume control; that's why I mentioned the one that was being sold for parts on eBay.

I know that you are an experienced technician, but for the sake of the others, it goes without saying that it would be advisable to remove the plastic volume and tuning wheels before any soldering is performed on any transistor pocket radio. It's so easy to take your mind off the soldering iron for one second, and accidently brush the iron against one of those wheels. That would be catastrophic!


Top
 Profile  
 
 Post subject:
PostPosted: Dec Sun 19, 2010 5:44 pm 
Member

Joined: Jan Mon 04, 2010 2:52 am
Posts: 3179
Wow John! Now I'm envious. I think that I will check out eBay for a Zenith Royal 500H radio, and purchase one for myself. I will look especially for one that's not working; then maybe I can get it for a decent price as you did. Most of the ones that I've seen on eBay are commanding a small fortune!


Top
 Profile  
 
 Post subject:
PostPosted: Dec Mon 20, 2010 2:39 am 
Member

Joined: Oct Mon 26, 2009 10:02 pm
Posts: 6177
Location: Indianapolis, IN
Thanks Blustar1,

I did have knobs off for soldering---reinstalled them to verify proper operation before reassembly... When I started collecting radios as a kid 40 years ago, did a lot of damage to cosmetics with poorly placed soldering iron ( still have at least one of those, a flip-top Motorola, and it is a grim reminder... ).

I did go ahead and bid on that parts set and got beat out just before end by a couple bucks---only went for $14.10 ! Would have repaired it to go alongside my black Royal 500B & two 500E's...
Be sure to post if you find one !

John


Top
 Profile  
 
 Post subject:
PostPosted: Dec Tue 21, 2010 10:43 am 
Member
User avatar

Joined: Apr Tue 25, 2006 5:51 am
Posts: 5124
Location: South Central, PA
Blustar1 wrote:
...I know that you are an experienced technician, but for the sake of the others, it goes without saying that it would be advisable to remove the plastic volume and tuning wheels before any soldering is performed on any transistor pocket radio. It's so easy to take your mind off the soldering iron for one second, and accidently brush the iron against one of those wheels. That would be catastrophic!


Good advice. Been there, done that on a Philco transistor radio...but, never again!

_________________
-John S.
RIP:Curt Reed, Alan Douglas, "oldradiospook", & "Bigbandsman"


Top
 Profile  
 
 Post subject:
PostPosted: Jan Wed 12, 2011 11:13 pm 
Member

Joined: Jan Mon 04, 2010 2:52 am
Posts: 3179
http://cgi.ebay.com/Vintage-Zenith-Roya ... 1c187e8f24

Hi John. You asked me to post if I found another Zenith Royal 500H on eBay like the one that I posted here. Here it is.


Top
 Profile  
 
 Post subject:
PostPosted: Jan Thu 13, 2011 2:22 am 
Member

Joined: Oct Mon 26, 2009 10:02 pm
Posts: 6177
Location: Indianapolis, IN
Hello Blustar,

I saw that one the other day and put a low bid on it ( and that was all...)---are you trying to get it ? Best of luck if so... Let us know what happens...

John


Top
 Profile  
 
Post New Topic Post Reply  [ 24 posts ]  Moderator: Dave Doughty Go to page 1, 2  Next

All times are UTC [ DST ]


Who is online

Users browsing this forum: No registered users and 3 guests



Search for:
Jump to:  




























Privacy Policy :: Powered by phpBB