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A site where discontinualed schematic diagrams and back dated information can be found on discontinued radios tv's and any electronic equipment can be found. Newer manuals either Service and operating manuals. Radio amateurs should find this site a great source for ham radio equipment manuals. I will return to this site should I need information on any electrical equipment. priced easy to download in a PDF format and print pages need to undertake the repair.
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Quality scan of the original. All the detail necessary to troubleshoot, repair and adjust the unit. I'm sure I will be downloading more manuals in the future as the need arises.
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Exactly as described, a Service Manual complete with the schematics and PCB layout delivered in a timely manner. Many thanks for the great service.
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some of the writing is a bit blur but the part in the schmatic was great and i have fixed the machine thanks
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Well.. I'd searched for this manual and although I found many copies online I was pleased to find your website with a well balanced pricing system and easy to search and follow links. That together with the very quick response time was just what I was looking for.. being a very impatient tech.. ;-) I had the service manual in front of me within a short time.
Bookmarked.. and you can bet I will always come here first for my service & user manuals..
best regards
Ed(Tony) Foley
G7WHK
Technical Description
Synthesizer
A 900 MHz RX synthesizer is used as first LO. The TX synthesizer is modulated and working at a fixed frequency of 90 MHz. The TX frequency is obtained by mixing the frequencies from the two synthesizers. The main synthesizer uses fractional-N to achieve lower phase noise and faster switching. In most applications the phase noise is proportional to the overall division ratio and since fractional-N uses a higher comparison frequency the phase noise will be lower. The auxiliary synthesizer is a conventional loop without fractional-N and the comparison frequency is 75 KHz. The RX VCO is a module which operates between 914.040 MHz and 938.970 MHz. The MALIN chip contains the TX VCO , TX buffer stage, TX mixer, RX buffer stage and the RX prescaler. The TX PLL, RX PLL and the lock detect logic are part of the BERTINDY chip.
Programming
The name of the PLL circuit is BERTINDY, which is a combination of the two chips Bertram and Cindy. A three line bus is used to program the synthesizer with the help of a clock frequency. The RX synthesizer is operating at 45 MHz above the required RX frequency and a 14.85 MHz reference frequency is used.
Power
The synthesizer part in BERTINDY is put in power down mode by sending a command to the chip. The auxiliary and main synthesizer can be powered down separately and the RX-VCO is controlled by BERTINDY. The prescaler and the 90 MHz VCO of MALIN is controlled by sending power up/down commands.
Lock Detect
A signal showing when the synthesizer is locked is implemented in BERTINDY. The lock detect circuit operates with both the main and the auxiliary synthesizers. If both synthesizers are enabled, the lock detect output becomes active when they are both locked. If only one synthesizer is enabled, the lock detect output becomes active when that one is locked.
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