Restoration of Datron 4910 - Page 1
Forum section: electronics / general

author: syau
author_rank: Frequent Contributor
timestamp: May 17, 2020, 11:37:12 pm
content: Finally have time to restore a 4910 which scored as part only. All output measured as 0.3V.Removed the top cover found that the seller already removed the batterybut leave no marking on how the cables being connected.Removed all cards from the until and took measurement on the connector found 12V present in P604 pin 12-10 and 12-11. However 5V not present P4 pin 9-8.Close inspection on the main board unable to find anything unusual except the 12 VDC not present on the connector that supply power to the adapter board that host the collector P4. Lucky all voltage converter on the main board are identical and I managed to found the top one (ref to the photo) has a failed ZVP2106A. Swapping the one next to it (For voltage reference #1) restore the 12V output.While still have the main board exposed, I also check the PCM clock at connector P604 pin 10, 11, 12, 13, 14 and all come good.Restored the unit, fitted back 3 voltage reference (except #1) and found all output has nominal voltage.Order placed to digi-key for some capacitor and the ZVP2106A.Note: The photo attached show the mosfet ZVP2106A already swapped over to the top power supply.

author: syau
author_rank: Frequent Contributor
timestamp: May 17, 2020, 11:46:26 pm
content: Replaced all the 10uF 25V tant cap (total 10) in the power supply board and powered it up overnight and found the output solid at 10.00000 V on my DMM7510.While playing around the voltage reference board found one board has one of the 2 small switch jammed, lucky digitkey also stock the switch 563-1385-ND.

author: CalMachine
author_rank: Frequent Contributor
timestamp: May 18, 2020, 01:57:44 am
content: If you ever want to sell the 4910, I'm your guy

author: syau
author_rank: Frequent Contributor
timestamp: May 18, 2020, 12:05:04 pm
content: 38Hot has a discussion on using Li-ion batteryhttp://bbs.38hot.net/thread-1023-1-1.htmlHere found a quick translation of the post:1. Replace each set of 6V lead acid battery (3 per set) by four 186502. Change the battery cut off voltage to 13V by replacing R412 to 73K, fine adjustment subject to testing by using a variable power supply and monitoring the cut off of Q401.3. Change R403 to 20k4. Adjust the R424 for a charging voltage of 17V (measure at the anode of D402)A copy of the power supply circuit diagram is provided in the 38Hot post which I repeated here.

author: syau
author_rank: Frequent Contributor
timestamp: May 21, 2020, 11:36:52 pm
content: Replaced the ZVP2106A and all the tantalum cap in the main board, 4 channels are up and running. According to 38hot, it is possible to use 18V li cells without modifying the circuit. Will do try to it locally.

author: syau
author_rank: Frequent Contributor
timestamp: May 24, 2020, 02:33:21 am
content: Isolated 4 output cell found 4 cell voltage distributed across 9.99999xx to 10.00001x on my 3458A

author: CalMachine
author_rank: Frequent Contributor
timestamp: May 24, 2020, 03:20:55 pm
content: Quote from: syau on May 21, 2020, 11:36:52 pmLet me know how that works out for you. My 4911 is missing batteries (but on a UPS) and had a weird battery mod installed before I purchased it... I haven't messed with it yet and was exploring options. Li cells could be a good option to pursue.

author: syau
author_rank: Frequent Contributor
timestamp: June 14, 2020, 01:44:32 pm
content: Received several 18V 4400mAh Li-ion battery pack from China. Each pack made up of ten 18650 cells.Voltage output without battery connected = 20.60 VVoltage across the battery terminal is 19.57 V with a charging current of 214mAhThe voltage across the battery is 19.49 V with a discharge current of 107mAh when main removed.Temporary installed 5 battery in the 4910 while pending for some spade terminals as I ordered the wrong size

author: Kleinstein
author_rank: Super Contributor
timestamp: June 14, 2020, 04:21:18 pm
content: Using Li cells is a 2 sided thing: there are limitation of the transport of Li cells, especially if actually in use. Chances are the Li cell version is no longer suitable for air transport.

author: syau
author_rank: Frequent Contributor
timestamp: June 16, 2020, 12:55:04 pm
content: Li-ion cell inside equipment still shippable by air with some administrative effort, or, just swap out with lead acid batteryThose Li-ion is only USD$ 13 per pack