Re: Lafayette LR-20 MPX Board
Nope T14 has the metal shield and slug missing. coil is busted and measures infinite or open. Found a 8.6 mH coil on Digikey for $2.42, however shipping charge $25.00. So I hope it will adjust from 6-9 mH. Checked dimensions with dial indicator and matches physical size for pc mount. T15 has the same part number and checked good at 6.3mH. Tested in Sencore LC 103 and adjusted from 4mH to 7.6mH. Could not find any specs on adjustment range on datasheets other than tolerances of +10 -10 %.
Schoenradt
Member
Last Activity: 05-18-2022, 10:28 PM
Joined: 01-25-2021
Location: Temperance, Mi
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Lafayette LR-20 MPX Board
Needing some help to get this MPX board working again. General investigation shows a busted variable inductor location T14. Looking at the schematic T14 and T15 are the same inductance value. Unsoldered T15 value measured was 6.3 mH. Coil was manufactured by Toko of Japan. Doing some research it appears that a 369SNS-1668Z is in this range. Also slug color is blue. Any guess where I can purchase this coil from and a price. Checked the usual Digikey, Mouser, and Newark no luck. Coil fits Toko 5KM series.... -
Re: Radio Shack 2200813 29 range DVM
Adding complete picture of main board component side....Leave a comment:
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Re: Radio Shack 2200813 29 range DVM
I have included photos of the main board and some tests using a known good meter and it isn't good....Leave a comment:
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Re: Radio Shack 2200813 29 range DVM
Yes the other ranges seem to work. I don't see any way to zero the ohms out as the meter reads about 46.7 ohms when leads are shorted. I'll send some more pictures of the main motherboard and some LCD readings.Leave a comment:
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Radio Shack 2200813 29 range DVM
Does anyone have any information for a Radio Shack 2200813 meter. I need to know what value R14 was. Mine is measuring 90 ohms. My meter did have a blown fuse F1 rated at 250V @ 500mA. Symptoms are meter doesn't measure DC mA correctly and beeps above 40 mA range if it is even giving proper current measurements. Below I have included some pictures and a macro shot of R14 on the pc board.... -
Re: Ocosmo E32 Backlight LED Replacement
These are the finished panels. I used a high gloss white enamel paint and then used a urethane clear glue to attach the lenses.
If you're wondering why the center panel is a little off white after the LED's it's because I masked off the part numbers for reference....Last edited by Schoenradt; 08-05-2021, 02:13 PM.Leave a comment:
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Re: Ocosmo E32 Backlight LED Replacement
Update: I took your advice and replaced all 21 LED's. I used my Hakko FR-801 set on heat range 4 and air at 10. Each lens popped off in a few seconds and just dressed up solder pads with fresh solder. I let the pads heat up until the solder was molten then placed the new LED on the pads and it seemed to seat by itself with gravity. Tested each LED after soldering to insure proper polarity and connection. I am going to mask the LED's off and paint the light strip with white glossy enamel spray paint to make the panel uniform as each replaced...Leave a comment:
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Re: Ocosmo E32 Backlight LED Replacement
Looks as I have found some that will work. All 3 for $12.35 from ebay.
Product information
Condition: Brand NEW
Size (Length): 630mm
Number of LED beads: 7 per strip
Every LED Lamp Voltage: 3V
Package include: Kit / 3pcs(1*B1+2*B2)
May have change connector or cut harness and solder directly to panel,...Leave a comment:
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Ocosmo E32 Backlight LED Replacement
Hello all reading this post. I have an Ocosmo E32 TV and have isolated the backlight problem to one defective LED. Testing the good LED strips I have found that each LED drops about 3.0VDC across it. Also from reading and using my DVM each LED draws about 350mA of current. My unit has 7 LEDS on each strip with a total of 21 LEDS. Guessing from this the series supply voltage should be 66 VDC. I have removed the defective LED from the LED strip and using my micrometer I'm getting a 3.5mm x 2.8mm layout. Would this be defined as a 3528 LED SMT? The next question what temperature is this LED 6000K?... -
Re: Jvc pc-x100
Success, Yes the CD player worked and I am convinced that plugging in the wrong wiring harnesses to optical pickup will render it useless. I had to some alignment calibration for tracking monitoring a symmetrical pattern on my oscilloscope but tried several CD's and all were able to play all the way through. I have another unit and it is not working with a new pickup so I am checking the op amps and driver transistors.Leave a comment:
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Re: Jvc pc-x100
Update: I believe I have isolated the problem. It would seem that the laser pickup has two identical interconnection sockets that are 8 pins each. One is red for the laser and the other white for the photo-diode array. The wiring harness plugs are both white and not polarized to the connectors. Plugging the wrong harness into the connector will fry the laser unit putting 5.0Vdc across the laser diode. Also it would seem that the photo-diode array is also rendered useless by plugging the laser diode supply connector to it. I have ordered the original KSS-210B pickup...Leave a comment:
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Re: Need schematic for JVC PC-X100
Here is the complete service manual.
It's about 17Mb...Leave a comment:
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Re: Need schematic for JVC PC-X100
I just bought one and it has some wrong values for resistor values in the cd section, but for the most part it is accurate. I can send the PDF service manual if you need it? Please check your message box?Leave a comment:
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Re: ECH81/6AJ8 Vacuum Tube Question
Update: Rebuilt FM front end replaced all dog bone capacitors with multi layer ceramic capacitors at 1% tolerance. Main defect was the 8.2pF and 20pF in the tank circuits for the mixer oscillator. Calculations with measured values showed that resonant frequency was 37 Mhz. New values put it back around 100 Mhz. Also B+ feeds were low due to high values of plate resistors 2, 10K resistors at 1 watt measured 12K and 11K so I will replace them with 1% metal film. Tuner response and selectivity is tremendous now. Attaching photo of rebuilt front ...Leave a comment:
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Re: Jvc pc-x100
I have successfully replaced the main IC's IC 602, and IC 603. The chips lifted quite nice and no traces tore up. The new ones went down well, but no spindle rotation.All I get on the display is CD then all zeros. I also replaced the optical pickup with the original laser unit KSS-210B. Still no disc read and yes I removed the solder bridge and the laser is on and the lens does focus. I have bought a servicing manual that should isolate the problem....Leave a comment:
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Re: ECH81/6AJ8 Vacuum Tube Question
The tuner front end is straight forward the components are soldered point to point. I am de soldering all the capacitors, but my Sencore LC103 does test capacitors in circuit. It has never given errors in values. I have removed some capacitors and they are over 20% out of tolerance for example the 10pF cap in series with the Antenna matching transformer measured 24Ppf that's not acceptable at over 100% out of specs. That will trash my 1st RF amplifiers gain and sensitivity. Also using the measured values my tank circuits are Resonant Frequency...Leave a comment:
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Re: ECH81/6AJ8 Vacuum Tube Question
Well I took the painstaking task of disassembly of the FM front end and boy oh boy every capacitor is well out of tolerance and value. Using reactance formula it seems that the impedance increases as the tank circuits are in the FM band. I have calculated that at 100 Mhz XL = 62 ohms and XC = 79 ohms. It seems that the first stage of the triode is exactly like a mosfet J-fet used as an RF amplifier. The two tank circuits must generate the beat frequency. which is then passed to the first IF transformer. I'm guessing that this frequency will be...Leave a comment:
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Re: ECH81/6AJ8 Vacuum Tube Question
My replacement ECH81/6AJ8 arrived today and yes AM is now superhetrodyning again. Getting very good sensitivity from 1600Khz to about 630Khz with just the loop antenna. Magic eye now shows center tuning lock on. Still not happy with FM sensitivity so I am going through the pain staking of removing the front end assembly and checking each component with my Sencore LC103 tester. Would like to tighten up the tank circuits and increase gain on first RF amplifier. It appears this tuner uses a tuning inductor rather than a tuning capacitor. I am assuming...Leave a comment:
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Re: ECH81/6AJ8 Vacuum Tube Question
I'm attaching the schematic and will note the 22V voltage drop for each anode of the rectifier tube. The schematic shows a 300 ohm @ 5watt resistor. Once I measure first the actual resistance and then the voltage across R26 I will know the actual current value. The schematic shows B+ at 200Vdc, but I'm using an isolation transformer dialed in at 117Vac. It seems that back then the engineers weren't too concerned about tolerances. I measure 190Vdc for B+1. So I will shoot for 200Vdc set for 120Vac line voltage on the primary of the transformer...Leave a comment:
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