I have one of the Philips Protelgram projection units in need of repairs to the optical surfaces (resilver). Has anyone had experience with Protelgram and can anyone recommend someone to do quality repairs on these optics?<BR>thanks.........<BR><P>------------------<BR>Pearson

H.L Clausing in Skokie, IL. can resilver the spherical mirror. I have had them do about 6 mirrors mostly for the RCA projection sets and a few other 12" and 13" sizes. Those run about $125 each, I've never had one of the smaller ones from the Protelgram done, so not sure of the price. If you decide to have it done, use their "Beral" coating it has a 91% reflectance rating. I had one mirror done with their "diamond-brite" finish which has a rating of 97% at double the price, I couldn't see a difference - wasted a lot of money on that one. <P>The flat mirrors aren't cost effective to have resilvered, so your best bet there is to put in a new mirror, a thin rear surface miror will work OK if you can't find a front surface mirror.<BR> <A HREF="http://www.clausing.com/main.html" TARGET=_blank>http://www.clausing.com/main.html</A> <P><BR>Chuck<P>------------------<BR> <A HREF="http://www.myvintagetv.com" TARGET=_blank>www.myvintagetv.com</A>

Having put forth extensive pain on Protelgram projection sets let me share some thoughts.<P>First, DON’T run the 3NP4 out of the optical box as it does emit X RAY’s.<P>I have never yet found flat, front surface mirror material that has enough reflectivity to work in one of these sets.<P>Maybe Chuck A could recommend a source.<P>The original mirrors are front surface Silvered, and only real Silver apparently has enough reflectivity to work here. <P>I have been trying for years to get a new mirror for in the lid for my Scott 6T11 to no avail.<P>You will have a concave front surface mirror and flat thick glass front surface mirror inside the optical box.. These are usually OK and can be VERY CAREFULLY Cleaned (if not previously ruined).<P>The aspherical corrector lens on top of the box came in several sizes (three I believe) for different throw distances. Sometimes these parts get switched around without regard to this resulting in difficulty in even focus across the screen.<P>I was always able to turn up usable optical box parts and HV supplies from various want-ad services, thinking there were lots of this around.<P>Protelgram was made by Norelco into the 1960’s I believe and they even had a three gun color package.<P>You want to make sure the High Voltage oscillator frequency is exactly 1,000 Hz (cycles per second for my generation). This controls the filament voltage on the three rectifier tubes (trippler) buried in the high voltage can. You can also dissemble the can but the little rectifier tubes (E-50) are hard to find and 5642’s wont work.<P>I actually have a fondness for these sets and use a Scott 6T-11 all the time (20 inch table top projection). I have had several of the Emerson sets. <P>The protelgram projection delivers a decent quality picture on the 20 inch size sets but I felt it was too dim when used with a separate beaded screen. The beaded screens usually have a lot more gain than the rear projection frosted glass however. <BR><P>------------------<BR>

Thanks Chuck & Jimmc, I'll be contacting Clausing tomorrow, their site indicates they can do the job.............<BR><P>------------------<BR>Pearson

Chuck A is correct (again). HA Clausing does a great job on the spherical mirrors. Like Chuck, I have only had the larger spherical mirrors resurfaced. But the price for the flat mirrors is based on surface area, so the small mirror in the protelgram should be reasonable. I do not think anybody uses silver for front surface mirrors, even though is is called "silvering" (or re-silvering). Most astronomical or projection mirrors use an aluminum (alloy), deposited of the surface as a vapor in a vacuum chamber. HA Clausing should have no trouble with the mirror(s) in a Scott 6T11, though the relatively large flat mirror is likely to be expensive. You might look for a front surface mirror out of a modern projection TV.<P>------------------<BR>

thanks John, I emailed Clausing but have not heard back as yet. I need the 2 mirrors in the optics box resilvered, the mirror in lid seems good. The flat one is about 7"x8", the concave one is 8"dia. <BR>thanks........<BR><P>------------------<BR>Pearson

Pearson,<P>Your best bet with Clausing is to call to get the current price. They will then just tell you to send the mirror with your information, they usually turn them around in 2 weeks or less.<P>As John said the best place for the flat mirror is from a contemporary projection set. Clausing told me they could do the flat mirrors but it would be costly and there was a good likelihood of breakage.<P>Unless the flat mirror in your set are really bad, you may want to just have the spherical done then decide. I have found that just doing the spherical one made the difference from a unusable set to a good performer. <P>The screen picture on my web of the RCA Berkshire is the result of just the new spherical mirror. I put a new flat mirror on a Philco 2500 and couldn't see any real improvement in the projected picture.<P>One last piece of advice, make sure you mark the position of the spherical mirror and the corrector lens before you take them apart, adjusting the mirror to corrector lens alignment can be a bitch. (from experience)<P>Chuck<P>------------------<BR> <A HREF="http://www.myvintagetv.com" TARGET=_blank>www.myvintagetv.com</A>

In my playing with Protelgram parts I fortunatly have never had to replace either of the mirrors in the box.<P>All of the mirrors in the path are out of focus so blemishes don't show (like that big hole the CRT passes through).<P>My trouble spot is the mirror in the lid of my Scott 6T-11 is a bit rough and it does show if you look real close. It is closer to the screen.<P>I have moved those aspherical correctors around and have never noticed any change. I have noticed that if you have the incorrect throw lens in place yo will never get even focus across the screen.<P>I like the protelgram sets and always thought them nifty.<P>Does anyone know of other manufactures who used Protelgram other than Scott 6T-11, Emerson 609 and 649.<P>Jim <P>------------------<BR>

The 1949 Delco # TV-201 console used the Protelgram system. Anyone have one of these?<BR>Thanks to all for all of the great info.........<P>------------------<BR>Pearson

Off the top of my head:<P>Emerson, Decca, FADA, Norelco<P>And I'm sure somebody (John) will pipe in with more.<P>Chuck<P><P>------------------<BR> <A HREF="http://www.myvintagetv.com" TARGET=_blank>www.myvintagetv.com</A>