Add a Plectron or Motorola Alert Crystal Controlled Monitor Receiver to Your Scanner Collection
Download Samsung R series Schematic Mother board, main board pcb info and schematics Schematics 4 Free Service manuals, schematics, documentation, programs, electronics, hobby. View and Download LG KP220 service manual online. KP220 Cell Phone pdf manual download. Service manual; LG KP220 Service Manual. Also See for KP220. Check L705, L706, R717,R718 Change U401 select test echo. R719, R719,R721,C719,C722 C741 will have 1.2MΩ Has shift, lose or open? Re solder the component Re-setting to. Samsung Np-r519 Laptop Manual Support and online pdf manuals for Samsung NP-R519. I want to reset my laptop as i have tried to restore it,but when im in restore there are boxes. Laptop Repair Tutorial Samsung NP RV510, RV511, S3510, S3511, R530, Repair Tutorial. You can read the recommendations in the user guide, the. Nov 27, 2001 Plectron Corporation, 01:09 PM. Does anybody know where i can get parts for a plectron R719. I need a AC adapter wire for the plectron i have. Im the 1st lt of a junior corp and we need one. Thanks for your help in advance Tags: None. Previous template Next. Download SAMSUNG NP-R519 R719 BREMEN-Q REV 1.0 SCH service manual & repair info for electronics experts. Service manuals, schematics, eproms for electrical technicians. Click on the link for free download! Document preview. Preview of SAMSUNG NP-R519 R719 BREMEN-Q REV 1.0 SCH 2nd page.
by Bob Parnass, AJ9S
[NOTE: This article may not be reproduced in whole or in part on CDROMS, in bulletin boards, networks, or publications which charge for service without permission of the author.]
In the 1960s and 1970s, thousands of firemen and ambulance squad members came to rely on their transistor Plectron and Motorola monitor receivers. They have now been replaced by portable pagers, and are often available at hamfests in the $5 - $25 range. Since many are in rough condition and need repair, a hamfest special is better suited for hobbyists who like to fix their own radios.
Plectron and Motorola crystal controlled receivers are excellent for dedicated monitoring of local frequencies -- a task for which you wouldn't want to tie up your 400 channel programmable scanner. They can be powered from 117VAC or 12VDC with the proper mobile cord. The audio quality of a Plectron P1, Plectron 700 series, and Motorola Alert Monitor is far better than any consumer grade scanner and the sensitivity, image rejection, and intermod immunity is outstanding when aligned properly.
The Plectron and Motorola Alert monitors are single band receivers: VHF-low, VHF-high, or UHF. No single Plectron or Motorola Alert monitor can cover the entire 30-50 MHz band, so there were versions optimized for each portion of the VHF-low band. There were different versions to cover low and high 'splits' in the VHF-high band, too. For example, low band R8000s come in 30 - 35, 35 - 39, 39 - 49, and 49 - 54 MHz versions. There are two VHF high band versions of the R8000: 148 - 158 and 158 - 175 MHz.
VHF-low band Motorola Alert monitors come in two splits: 30 | - 42 and 42 - 54 MHz. |
Although UHF versions of the 700 series were made, they are somewhat rare and coverage is limited to 470 MHz and below.
Plectron made several models with dozens of different options. Both the original P1 and later 700 series are suitable for restoration, although I prefer the newer 700 models. The 8000 series were even newer and very desireable, but they are difficult to find at hamfests. The Plectron 500 'economy' series is less desirable.
The P1 series have black cabinets with a blue-green and silver color scheme used on the front panel. They were made in the Chief (tone decoder & carrier squelch), Patrol (carrier squelch only), and Sentry (tone only) models. The Sentry models lack a carrier squelch and therefore are of little use to hobbyists except for scavenging parts. Model number and frequency information appears on a gummed label on the rear panel:
The R700 series have black cabinets with brown front panels and are slightly smaller than the P1 receivers. R700s were made in the Chief (tone decoder & carrier squelch) and Patrol (carrier squelch only) models:
The R8000 series are much smaller than the P1 and R700 and are housed in metal cabinets of various colors. The R8000s | use the same MC3357 IF/detector/squelch IC used in crystal scanners, but their crystals are not interchangeable with ordinary scanners. R8000s were made in the Chief (tone decoder & carrier squelch) and Patrol (carrier squelch only) models:
The Plectron FM Receiver/Recorder is a collector's item. It is essentially a 700 series Chief receiver with a built in cassette tape recorder. The recorder is carrier activated and can tape transmissions while the receiver is unattended. A connector on the rear panel allows for all kinds of remote control possibilities.
I use two Plectron P1s and four R700s in my living room, seven R700s down the ba***t, and several Plectrons and Alert Monitors stored in reserve. The ba***t Plectrons are turned on automatically when someone walks downstairs. Power to them is controlled by a modified Radio Shack Safe House infrared motion detector, originally sold as an intrusion alarm.
When a rescue squad member from Missouri advertised a number of Plectrons on USENET, I bought them -- all 20+ of them. I cleaned, fixed, and restored each one. After recrystalling them on local frequencies, I distributed them to members of my scanner club who were glad to get them.
Both brands of receiver require special crystals. I sometimes use Radio Shack's generic 3rd overtone scanner crystals in the Plectrons but they oscillate on frequencies far away from their marked frequencies. That's because the Plectron oscillator is designed to be used with a crystal which oscillates on its fundamental, not overtone, frequency.
AC power cords for both types of receivers use unique connectors and are scarce. You can buy them new but it's much cheaper to drill a hole on the rear panel and attach a permanent a power cord. Make sure you use a grommet in the hole to prevent the metal chassis from chafing the line cord.
Many Plectrons and Alert Monitors were equipped with an internal NiCd battery pack, intended to power the receiver if the AC power fails. It's unusual to find a used monitor receiver with the NiCd pack still capable of holding a charge. More often, the batteries have died and the series charging resistor has overheated and burned. Be sure to remove the dead batteries as they often leak.
Plectron Scanner
If you find the squelch on your Plectron 700 series receiver has too much hysteresis, replace R96, a 180K resistor, with a 560K resistor. On the P1, the resistor is designated R81.
I have not used the Plectron tone alerting features so I cannot address that except to say that the special coils and capacitors for the dual tone decoders vary depending on the tone frequencies and are somewhat difficult to obtain. Repair service for the Plectron P1 and R700 models is offered by:
Woodson Electronics Plectron Place P.O. Box 960 Imboden, Arkansas 72434
telephone 1-(501)869-7985
Plectron Radio
Some replacement parts are currently available from Federal Signal in University Park, IL, phone (800)524-3021. You can also get Plectron repairs and parts from:
Northeast Communications 4 Oak Ridge Rd Newfoundland NJ 07435 201-697-8804
Alert Monitor parts are available from Motorola. Phone (800)972-3226.
I currently have no Plectrons or Motorola Alert Monitors for sale. I'm hoarding them. :-)
--
Locate & identify transmitters in your area with a color RadioMap(tm)