AST-3G Plus II
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AST-3G Plus II
| Preliminary Information | |
|---|---|
| Release Year | 1987 |
| Leak Risk | Medium |
| Batteries | None |
| Mounting Technology | Through Hole |
| Capacitor Types | Aluminum Electrolytic, MLCC |
| Destructive Entry | No |
Jumper settings and other info here
Known Issues
Three electrolytic capacitors are leaking, try to replace
Causes
- Produced in 1987, electrolytic capacitors are prone to leakage
Solutions
- Recapping
Disassembly Notes
The leaked electrolyte corrodes and causes solder oxidation, which makes it difficult to desolder. Be careful to avoid high temperature damage to the pad
Original Parts
AST-3G Plus II (C)AST 1987, FCC ID: DJK 68Y AST3G
PCB Mark: 202161-303A Silkscreen: 202161-003
| RefDes | Qty | Capacitance | Voltage | Mount | Diameter/Size | Height | Lead Spacing | Temp | Type | Brand | Series |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Others | 23 | 100 pF | Through Hole | 2.0 mm | MLCC | 104 | |||||
| C35 | 1 | 2.2 pF | Through Hole | 2.0 mm | MLCC | 222 | |||||
| C26, C27, C28, C29, C30, C31, C32, C33 | 8 | 47 nF | Through Hole | 2.0 mm | MLCC | 47K | |||||
| C1, C2, C3 | 3 | 22 µF | 16 V | Through Hole | 5 mm | 5 mm | 2.0 mm | 85 °C | Aluminum electrolytic | ELNA | 018 H |
| RefDes | Qty | Model Number/Part Number | Manufacturer (If Applicable) | Explanation | Datasheet |
|---|---|---|---|---|---|
| U1, U2, U3, U4, U5, U6, U7, U8 | 8 | KM41C464P-10 | Samsung(?) | Dynamic RAM | Memory Guide |
| U9 | 1 | P82C435 | CHIPS | Enhanced Graphics Controller | Link(click link, then click the download icon) |
| U11, U12, U13 | 3 | DM74LS244N | National Semiconductor | Octal 3-State Buffer/Line Driver/Line Reciever | DM74LS244 |
| U14 | 1 | LM339N | National Semiconductor | Quad Differential Comparator | LM339 |
| U16 | 1 | 74LS153N | Signetics | Dual 4-Line to 1-Line Data Selectors/Multiplexers | SN74LS153 |
| U17 | 1 | 74LS151N | DM74LS151 | ||
| U18 | 1 | SN74LS74AN | Motorola | SN74LS74A |
Replacement Parts
0805 SMD 22uF 16V - 50V 10%
The lead spacing is too limited, I'd like use SMD on back of PCB where the through holes are filled with solder.
| RefDes | Qty | Compatible Part Number | Order Links |
|---|---|---|---|
| Digikey |
Through Hole Capacitors
| RefDes | Qty | Compatible Part Number | Order Links |
|---|---|---|---|
| C1, C2, C3 | 3 | ECE-A1CKS220 / 25MH522MEFCT56.3X5 | DigiKey Mouser LCSC |
| C26, C27, C28, C29, C30, C31, C32, C33 | 8 | K473K15X7RF53L2 / CD1H473KC9BER1E100 | DigiKey Mouser LCSC |
| C35 | 1 | FG28C0G1H2R2CNT06 / 561R10TCCV22 | DigiKey Mouser LCSC |
| Others | 23 | K101J10C0GF5UH5 / CC1H101KC1EDSL4B1100 | DigiKey Mouser LCSC |
| RefDes | Qty | Compatible Part Number | Order Links |
|---|---|---|---|
| U11, U12, U13 | 3 | SN74LS244N | DigiKey Mouser LCSC |
| U14 | 1 | LM339N | DigiKey Mouser LCSC |
| U16 | 1 | SN74LS153N | DigiKey Mouser LCSC |
| U17 | 1 | SN74LS151N | DigiKey Mouser LCSC |
| U18 | 1 | SN74LS74AN | DigiKey Mouser LCSC |
If parts are not available or different selection is preferred, you can use the values in the Original Parts section to perform a parametric search.
Kits
- Digikey BOM: https://www.digikey.com/