Designs we love to hate!
 

Sick of that PCB that you have to remove from the chassis to work on? Disintegrated yoke cover creating a shock hazard? That series string chassis a little too hot for you? Well, you've come to the right place to gripe about it!

In all the time I've been here I've never seen a thread on this topic despite many threads dedicated to other topics containing discussions of bad designs...So I made this thread.

"So what makes you come up with this now?", you ask. Well...Last night I was up obscenely late working on my Silvertone roundy, and things were not going well.... The set needed a convergence adjustment, and I was trying to find the cause of slow intermittent loss of luminance followed by picture. The intermittent was being less cooperative then I wanted so I was waiting it out doing the convergence.
To make a long story short one of the blasted static convergence magnets fell out, and disappeared!

http://i1095.photobucket.com/albums/...y/DSCN0453.jpg

This convergence yoke is a BAD design IMHO. The white plastic static adjusters can be removed and lost (though that has never been a problem for me), the black magnets in those adjusters are not secured in by anything other then pressure of the plastic, and get lost very easily (this is not the first time they have disappeared! :gigglemad ). On top of that the brass clamps those adjusters slide in are mounted to the coils at least on one of their two mounting points with TAPE!...And it predictably gets old and breaks turning the mount into a spring and making the adjuster move as soon as you let go of it... And lastly the brass springs that make it stay put on the neck some times go shooting off when the cover is moved.

I'm so fed up with it that if I had one of the newer all plastic ones laying around I'd switch to that, originality be damned!

So what designs make you want to kick someones but?

Hands down, the WORST had to be those original b&w vertical chassis RCA with pc boards. There was simply no way to access the underside of the boards without cutting and peeling away the chassis sheet metal.

A close runner-up had to be those coil forms in Zenith color sets that crystalize with heat and fall apart (i.e., the 'efficiency' coil and the blue adjustment coils on the convergence board.

Well, I remember being pretty POed the first time that I found out that CRTs were sometimes designed with metal cones that were in many cases exposed. Not only did I get a heck-of-a shock while reaching for an unlit tube in a 17" RCA set, I tore a big gash in my arm on the sharp edge of the metal cabinet as I jerked back. :( Never did that again!

jr

I could piss & moan ( P&M) all day abt serviceability.

Wires to short to flip out the chassis to troubleshoot. Many.

No bottom plate, especially on audio stuff. Almost all.

No markings on PCB. Zenith

Special tools to pull HV wire out of the FBT. Sony

Moon shot power supply designs. Blame Energy Star.

Service lit only on fiche or disk.

Unremoveable safety screens. Old sets, many.

One thing I learned was most the time the engineers built a
high quality & serviceable set. Then they send it to sales.
Those guys are so cheap they wouldnt pay a dime to watch
the Statue of Liberty take a leak. So you wind up with a 20"
AC cord ( Sylvania ) to save 3 cents on every ten. Blame the bean counters.

nuf sed

73 Zeno

HA-HA !

Funny.... EM - So are they helper magnets?? Never seen that one....
I have to agree on stupid mechanical design items like that.... Looks like it was made
(designed) to need service (picture alignment) if you (customer) got mad at
something on tv and hit it ! !

I also very much hate the moon shot power supply designs, and the wires too short
to pull the chassis out and run the set so you can get in there to check something....

My first year in tv service I got a boom box from Sharp and up till then I never even
knew there was such a thing as paint on resistors.... I opened up this thing and it looked
like the board had parts labeled but the actual resistor was not there ! ! Since it was
on boom boxes, when people dropped them and the board for a fracture the resistors
would open..... Frustrating at first, but a short lived problem....

I don't know what you mean by helper magnets. They are the static convergence magnets....You know how on the newer yokes how there is a knob on each petal of the convergence clover (yoke) to adjust the static convergence?....Well mine has those dumb white plastic sticks with magnets on the ends instead of knobs....They are less smooth to adjust than knobs too, and I can see why once the new kind was created they fell out of use FAST.

Zeno: I never knew Sylvanias had 20' cords. I can see that being useful for lugables and movable cart/stand dwellers, but it was probably terribly awkward on consoles.

I hate when wires are too short on table sets to use the set as it's own test jig!



I still have not found the damn magnet! :sigh: But if I do I'm gluing it into the plastic like I'm in the process of doing on the remaining two.

Like this one: http://www.wa2ise.com/radios/rcatvback.jpg
I didn't even try to get underneath the boards when I did a recap. I just clipped the leads at the body of the old wax cap, and then did a J hook connection to the replacement cap leads and the now pigtails to the circuit board. Not the prettiest method, but it worked fine and it's hidden, facing the back of the CRT.

My father hated Emerson radio sets, they used to bury some parts under other parts, and you'd have to remove the top layer to replace something underneath.

Sorry I didn't see that the normal turn adjustments at the ends of the coils
were not there..... I guess they saved a lot.......

Old_Coot - I guess they thought no one would ever need to work on those sets....

.

Can you up-end the set without anything else falling out?

Anyway, anything with a bonded yoke gets my vote. Also, the '89 Panny console I had with the controls behind a door under the screen; tiny buttons with labels I couldn't see without getting down on all fours, and the picture controls right in there with power/volume/channel. How easy it was to hit those and mess up the picture.

Probably, the chassis is out...Last time I worked on it with the chassis in I lost a screw and had to shake the set to find it...My back did not like me after shaking that table model roundy. I actually hope the magnet did not land inside the set since finding a flat black colored, pea sized magnet inside a flat black metal cabinet is not an easy task...

I used to recap the vertical circuit in those RCA's, even when they were newer. There wasn't that many leads that had to be disconnected to gain access to the foil side. There was several caps, that had to be replaced.
The cap across the horizontal sine wave coil, .01 mfd @ 600v could be replaced, by reaching through the chassis holes.
The set pictured, is it a KCS108???. Don't let the chassis slip off the bottom rail, there goes the neck. :sigh:

Mitsubishi and the fish oil caps! Once you smell the tell tale smell, get ready to buy a new tip for the soldering station! Surface mount microscopic resistors! The GE "swiss cheese" chassis! As bad as the RCA! Panasonic's "Prism" that blasted the neck of of it's CRT like Zenith with bad safety cap and on the same set, the inability to get the board out to repair vertical IC connections! Funai VCR that requires you to unsolder those wonderful wiring harness' to get the transport off the board! Transistors and IC's that have the part number removed at the time of manufacture! And don't forget the Sony TV with the double foiled mother board and daughter boards that were SOLDERED in! Removing the daughter boards always resulted in broken traces that took forever to repair! :thumbsdn:

It's this set http://www.wa2ise.com/radios/cooper%20tv.jpghttp://www.wa2ise.com/radios/rca21t8395.jpg
I don't remember what the chassis number is, too lazy to walk across the room and pull the back off... :D

Doggone. I dint mean to sound unkind toward that RCA. It was sed from the servicing perspective back in the day. If a shop didn't have a test tube or extension cables, there was no way to effectively troubleshoot (we did have those items BTW).
We got a few of those RCAs as trade-ins and somebody had literally cut and peeled back the sheet metal to get at the foil side of the boards.
From the design perspective, it was a "What were they thinking?" kind of deal.

I was actually able to recap my vertical chassis RCA by soldering through those holes on the back chassis side. Slow and painful, but doable. You need a pencil iron, not a gun, and a very good movable light source.