dunno about other revisions or brands of transmitter but on my hamilton some of the parts lack p/n's on them.
There is some equipment where the circuitry is in a big epoxy block and no one can even trouble-shoot it. I had a two-line telephone switch-button thing, and it had chronic static, the trouble was INSIDE an epoxy block!
Get the hammer. Smash it!
It's kind of a dirty trick erasing part numbers on components.
"You can always trace out the schematic on the circuit board."
That could present an interesting challenge if the circuit your attempting to put to road map is built on a multi-layer foil pattern PC board...you know..the ones that have foil traces sandwiched in layers INSIDE the PC board that you cannot see where it goes or if it intercepts another foil trace somewhere within the sandwich.
YUM!
RFB
"on my hamilton some of the parts lack p/n's on them."
That is so chicken ****. You don't see Harris or BE or any other like that hiding part numbers or schematics. They too have proprietary circuitry. EW did that on the FME-5k/10k PLL IC and later was figured out to be a PLL chip commonly used in Delco AM/FM digital tuned radios.
One of the many reasons why I don't invest in equipment where it's maker has to resort to cheating and cornering people like a tire salesman having a huge 10 dollar tire sale, everyone shows up and the tire salesman has a dude out in the parking lot poking holes in everyone's tires so they have to buy new ones. Not exactly an honest nor honorable way of doing business.
Some would say well a Harris transmitter is considerably more expensive thus a schematic and part numbers are provided. Well put on a comparable scale to a budget of hundreds of thousands vs a budget of a few hundred, there is no valid reason or justifiable reason for scraping part numbers and hiding schematics. 700 bucks is NOT CHEAP! There better be a schematic and part numbers on those components otherwise my business goes elsewhere...and it has.
CHEATERS! JMO
RFB
First off Robert, glad you got it working. I have found that when frustration strikes it is time to go away for a while and do something else to cool off. Coming back with fresh eyes many times allows me to see the problems I initially missed.
The discussion about schematics and technical documentation revives memories. Before the introduction of LSI electronics into home devices schematics were available for almost any consumer electronics product. Some may remember SAM's Photofacts. For all my TVs I ever owned except the current flat screen I obtained technical reference manuals and effected the repairs myself using this information. All of my ham gear is documented with schematics and this seems to be the expectation of the customers.
In the past, some TV manufacturers made available schematics but used branded part numbers to force the purchase of replacements to be made from them. RCA did this with their televisions but at the same time made available the SK series of replacement parts which also covered non RCA brands, but it kept the business in their own house.
But there are other reasons a manufacturer may want to keep the schematics and part numbers hidden. It may be for a matter of safety, maintaining certification, or other legitimate reasons. To do so to keep the design from being copied is not a good reason since those intent on doing so will reverse engineer the product (consider the DVD copy protection fiascoes) while hindering those who are able from repairing their own equipment.
If I am spending many hundreds of dollars for a part 15 transmitter I expect to have a schematic available so I can keep it running myself. No schematic, no sale. I do recognize that those who buy and use equipment as appliances probably have no interest in nor understanding of what is inside and they could care less about this as long as it works and they can pay to get it repaired. That being said, I can not immediately think of any of the active posters here who are in this category judging by the technical discussions seen on this site.
Fortunately, as far as I know, the part 15 transmitter kit providers make their schematics available and repairs and even design improvements are thus enabled. This can significantly advance the hobby as it has with ham radio.
Neil
YES I was there for the era of Sams Photofacts and have many in my equipment files, including the Blonder-Tongue Audio Baton, the world's first multi-band equalizer filled with 12ax7 tubes.
There was another method for consumer video cameras, VCRs and perhaps some audio equipment... the "Service Manual."
The equipment itself came with a "User Manual," but the circuitry was only available to someone who factory ordered the "Service Manual" sometimes as much as $75. I've got heaps of those, too.
Computer equipment and peripherals may possibly mark this present era of equipment used both by consumers and professionals, no schematics available. If it's broken, throw it away and buy a new one.
The certified AM transmitters are probably not throw away, I imagine they can be serviced by the makers.
But with LPB that method of doing business is now a classic example of a failed system.
"But with LPB that method of doing business is now a classic example of a failed system."
LPB never hid their schematics nor did they ever scrape away part numbers, nor did they ever change part numbers to some odd ball unrecognizable number. Every manual to every product LPB made and marketed came with a complete schematic and original part numbers.
Remember, LPB failed due to it's new ownership and their very bad business decisions, had nothing to do with the products or literature at all.
Sure they would print in the manuals to send the units to them for repairs, but they NEVER forced any customer to glare at blank parts or blank pages in the manuals.
RFB
Point well taken RFB. Yes, LPB sent schematics. So can I recover at all from my way of pointing a finger at them?
Not much, the problem is really something different...... no backup plan to serve customers following the poor decision to deconstruct the company.
I think I'll go out and cut grass.
"no backup plan to serve customers following the poor decision to deconstruct the company."
So who's out there providing service for all those rigs and radios no longer made much less the company that made them even in existence anymore?
How did that TX 2-20 get on the air, and about to have a freq change in it's LPF...who's providing the customer service there?
Why..you are! 😀
Let's see....there's some remember when talk about Sams Photofacts and ham kit rigs...ahh Heathkit...such a relaxing but also an exciting word to hear and say.
Being the teacher and student has it's rewards. 😉
RFB
I am right on the one side of the discussion, the LPB era ended with no backup plan; no support plan for customers.
BUT, with amazing good luck for those privileged to be members of part15.us, there has proven to be A BACKUP ACCIDENT, by the name of RFB.
Without any doubt my carrier current would NOT be on the air today without the valuable assistance. NO THANKS to the destructors of LPB.
Now, what kc8gpd needs to document his 1000 is another good accident. There is no formal plan to serve his request.
LPB published schematics for many of of its products on its website, but a notable exception was the AM 2000, which was ultimately displaced by the Rangemaster. No schematic for the AM 2000 was ever made available to the public.
I was on The Wayback Machine reading part 15 stuff from the past, and I read that the LPB-2000, the part i5 transmitter, was believed to be a new version of USI TA-100, a transmitter I have never heard of before.
Anyone know?
"No schematic for the AM 2000 was ever made available to the public."
http://home.att.net/~weatheradio/part15.ht m">SOURCE: LPB, Inc. Offers many low-power broadcasting options, having been pioneers in the field. Most of concern to potential neighborhood broadcasters: the AM-2000, Part 15 Certified AM transmitter. This unit is a newcomer to the low power AM arena, but actually appears to be a re-branded USI TA-100, which is a venerable rig. Not that this is a bad thing, mind you. Just an observation. Another reason it is suspected that the AM-2000 is merely a USI-made unit is that LPB are authorized distributors for USI. It is enclosed in a weatherproof metal box, has a built-in tuning meter and is PLL synthesized, DIP-switch selectable. It also has a separate "brick" power supply which stays inside. Price is around $1,800 each.
Probably why no schematic to that 2000 unit.
RFB